The influence of surface lithium residue to the performance of LiNi0.9Co0.05Mn0.05O2 cathode materials

Liu Junjie,Chu Chenxiao,Qin Xianzhong,Meng Weisong,Xu Xinrui,Wang Bo,Cai Feipeng 한국세라믹학회 2023 한국세라믹학회지 Vol.60 No.3

High nickel ternary cathode materials (Ni ≥ 90%) have great potential for application as power batteries in electric vehicles and have become a hot spot for research on cathode materials. However, the residual Li on the surface of the high Ni ternary cathode materials prepared by solid-phase sintering is one of the main reasons affecting their electrochemical performance. It is found that Li1 + x(Ni0.9Co0.05Mn0.05)1-xO2 with x = 0.3, which has a discharge-specific capacity of 205.74 mAh g −1 at 2.7–4.3 V, 0.1C and 184.1 mAh g −1 at 1 C, retained 89% of its initial discharge capacity after 100 cycles at 1 C. The discharge-specifi c capacity at 10 C was 153.14 mAh g −1. In addition, the Li residue of NCM90-1.03 was 17,189.959 ppm, and the total alkalinity was 4196.896 ppm. The results by X-ray diff raction (XRD) and scanning electron microscope (SEM) showed that when the Li excess was 0.3%, it was possible to obtain uniform particle size, a wider Li layer, and reduced cation mixing. Therefore, choosing the right amount of excess Li can stimulate the application prospect of NCM90 in new energy vehicles.

Sensorless initial position estimation strategy for PMa‑SynRM drives based on dual rotating high‑frequency signal injection

Liu Liu,Pan Luo,Junjie Zhao,Yuechen Rui 전력전자학회 2023 JOURNAL OF POWER ELECTRONICS Vol.23 No.11

The rotating high-frequency (RHF) signal injection method is widely adopted for the initial position estimation in sensorless permanent magnet-assisted synchronous reluctance motor (PMa-SynRM) drives due to its simple implementation. However, the position estimation accuracy of the conventional method may be seriously deteriorated by the dead-zone effects of the inverter and the cross-saturation effects of the machine. Thus, to improve initial position estimation accuracy, a strategy to apply dual RHF signals is proposed in this paper. Different from the traditional solution, the proposed method sequentially injects dual RHF carrier voltages with the same frequencies but different amplitudes into the machine. Objective equations that consider the dead-zone and cross-coupling effects can be extracted from high-frequency response currents in turn. After the simple calculation, the initial position can be obtained directly and accurately, which effectively minimizes the influences of machine cross-saturation and inverter nonlinearities. The influence of the system delay on the rotor position estimation is also analyzed and deduced in detail. Finally, experimental results on a 5.5-kW PMa-SynRM indicate that the proposed method can achieve precise initial position estimation under any rotation position.

Glucocorticoid-induced expansion of classical monocytes contributes to bone loss

Liu Pei,Gao Youshui,Luo Pengbo,Yu Hongping,Guo Shang,Liu Fuyun,Gao Junjie,Xu Jianzhong,Wang Shengdian,Zhang Changqing 생화학분자생물학회 2022 Experimental and molecular medicine Vol.54 No.-

Classical monocytes are commonly involved in the innate inflammatory response and are the progenitors of osteoclasts. Excess endogenous glucocorticoids (GCs) can increase the levels of classical monocytes in blood and bone marrow. The role of this cell population in high-dose exogenous GC-induced osteoporosis (GIOP) remains to be elucidated. In this study, GIOP was established in rats and mice by daily methylprednisolone injection, and monocyte subsets were analyzed by flow cytometry. We demonstrated that classical monocytes accumulate in bone marrow during GIOP. Similarly, the monocyte proportion among bone marrow nucleated cells was also increased in patients with steroid treatment history. We sorted classical monocytes and analyzed their transcriptional profile in response to GCs by RNA sequencing. Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis showed that classical monocytes isolated from GC-treated rats exhibited osteoclast differentiation potential. Deletion of classical monocytes by clodronate liposome treatment prevented GIOP via inhibition of osteoclastogenesis and restoration of CD31HiendomucinHi vessels. Regarding the molecular mechanism, classical monocytes express high levels of glucocorticoid receptors. In vitro treatment with GCs increased both the percentage and absolute number of monocytes and promoted their proliferation. In summary, classical monocytes mediated GC-induced bone loss and are a potential target for therapeutic intervention in GIOP treatment.

CT-Based Leiden Score Outperforms Confirm Score in Predicting Major Adverse Cardiovascular Events for Diabetic Patients with Suspected Coronary Artery Disease

Liu Zinuan,Ding Yipu,Dou Guanhua,Wang Xi,Shan Dongkai,He Bai,Jing Jing,Chen Yundai,Yang Junjie 대한영상의학회 2022 Korean Journal of Radiology Vol.23 No.10

Objective: Evidence supports the efficacy of coronary computed tomography angiography (CCTA)-based risk scores in cardiovascular risk stratification of patients with suspected coronary artery disease (CAD). We aimed to compare two CCTAbased risk score algorithms, Leiden and Confirm scores, in patients with diabetes mellitus (DM) and suspected CAD. Materials and Methods: This single-center prospective cohort study consecutively included 1241 DM patients (54.1% male, 60.2 ± 10.4 years) referred for CCTA for suspected CAD in 2015–2017. Leiden and Confirm scores were calculated and stratified as < 5 (reference), 5–20, and > 20 for Leiden and < 14.3 (reference), 14.3–19.5, and > 19.5 for Confirm. Major adverse cardiovascular events (MACE) were defined as the composite outcomes of cardiovascular death, nonfatal myocardial infarction (MI), stroke, and unstable angina requiring hospitalization. The Cox model and Kaplan–Meier method were used to evaluate the effect size of the risk scores on MACE. The area under the curve (AUC) at the median follow-up time was also compared between score algorithms. Results: During a median follow-up of 31 months (interquartile range, 27.6–37.3 months), 131 of MACE were recorded, including 17 cardiovascular deaths, 28 nonfatal MIs, 64 unstable anginas requiring hospitalization, and 22 strokes. An incremental incidence of MACE was observed in both Leiden and Confirm scores, with an increase in the scores (log-rank p < 0.001). In the multivariable analysis, compared with Leiden score < 5, the hazard ratios for Leiden scores of 5–20 and > 20 were 2.37 (95% confidence interval [CI]: 1.53–3.69; p < 0.001) and 4.39 (95% CI: 2.40–8.01; p < 0.001), respectively, while the Confirm score did not demonstrate a statistically significant association with the risk of MACE. The Leiden score showed a greater AUC of 0.840 compared to 0.777 for the Confirm score (p < 0.001). Conclusion: CCTA-based risk score algorithms could be used as reliable cardiovascular risk predictors in patients with DM and suspected CAD, among which the Leiden score outperformed the Confirm score in predicting MACE.

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.

Optimal Isosceles Trapezoid Cross Section of Laterally Loaded Piles based on Friction Soil Arching

Junjie Wu,Changdong Li,Qingtao Liu,Fusong Fan 대한토목학회 2017 KSCE JOURNAL OF CIVIL ENGINEERING Vol.21 No.7

The paper presents a novel analytical solution to determine an optimal isosceles trapezoid cross-section of stabilizing piles subjected to the lateral load. In view of the pile-soil interaction mechanical analysis on the friction soil arching between the adjacent stabilizing piles, a general mechanical model for analyzing the behavior of the laterally loaded stabilizing piles with isosceles trapezoid cross-section is put forward. The reasonable net pile spacing expression for all kinds of isosceles trapezoid section piles is established via the analytical deduction, and it indicates that there is a positive relationship between the reasonable net pile spacing and gradient of pile sidewall. In consideration of the strength failure possibility in the apex of friction soil arching, the complete expressions of both the gradient of pile sidewall and corresponding reasonable net pile spacing of stabilizing piles can be established. The case study of Jinle landslide verifies that the reasonable pile spacing obtained by the presented model is slightly greater than that of the conventional design scheme, which shows that the stabilizing piles with optimal isosceles trapezoid cross-section can results in reducing the investment of the whole stabilizing piles.

Diffusion-controlled adsorption kinetics of aqueous submicellar and micellar solution at air/solution interface in the limit of short time

Junji Liu,Ying Zhang 한국화학공학회 2006 Korean Journal of Chemical Engineering Vol.23 No.5

γeq of aqueous Pentaethylenglycol-monodecylether (C12E5) solutionsat temperature 25oC were measured by means of Wilhelmy plate method and the determined critical micelle concen-tration (cmc) is 6.8×102 mol·m3. To study adsorption kinetics of aqueous submicellar and micellar solutions, the dy-namic surface tensions γ(t) were measured by means of maximal buble pressure method. Using the derived equa-sorption kinetics was studied. For micellar solution (c0>cmc) of C12E5, the demicellization constant was calculated.

Transcriptomic Features of Echinococcus granulosus Protoscolex during the Encystation Process

Junjie Fan,Hongye Wu,Kai Li,Xunuo Liu,Qingqing Tan,Wenqiao Cao,Bo Liang,Bin Ye 대한기생충학ㆍ열대의학회 2020 The Korean Journal of Parasitology Vol.58 No.3

Cystic echinococcosis (CE) is a zoonotic infection caused by Echinococcus granulosus larvae. It seriously af- fects the development of animal husbandry and endangers human health. Due to a poor understanding of the cystic fluid formation pathway, there is currently a lack of innovative methods for the prevention and treatment of CE. In this study, the protoscoleces (PSCs) in the encystation process were analyzed by high-throughput RNA sequencing. A total of 32,401 transcripts and 14,903 cDNAs revealed numbers of new genes and transcripts, stage-specific genes, and differ- ently expressed genes. Genes encoding proteins involved in signaling pathways, such as putative G-protein coupled re- ceptor, tyrosine kinases, and serine/threonine protein kinase, were predominantly up-regulated during the encystation process. Antioxidant enzymes included cytochrome c oxidase, thioredoxin glutathione, and glutathione peroxidase were a high expression level. Intriguingly, KEGG enrichment suggested that differentially up-regulated genes involved in the va- sopressin-regulated water reabsorption metabolic pathway may play important roles in the transport of proteins, carbo- hydrates, and other substances. These results provide valuable information on the mechanism of cystic fluid production during the encystation process, and provide a basis for further studies on the molecular mechanisms of growth and de- velopment of PSCs.

Deadbeat and Hierarchical Predictive Control with Space-Vector Modulation for Three-Phase Five-Level Nested Neutral Point Piloted Converters

Junjie Li,Xiangyu Chang,Dirui Yang,Yunlong Liu,Jianguo Jiang 전력전자학회 2018 JOURNAL OF POWER ELECTRONICS Vol.18 No.6

To achieve a fast dynamic response and to solve the multi-objective control problems of the output currents, capacitor voltages and system constraints, this paper proposes a deadbeat and hierarchical predictive control with space-vector modulation (DB-HPC-SVM) for five-level nested neutral point piloted (NNPP) converters. First, deadbeat control (DBC) is adopted to track the reference currents by calculating the deadbeat reference voltage vector (DB-RVV). After that, all of the candidate switching sequences that synthesize the DB-RVV are obtained by using the fast SVM principle. Furthermore, according to the redundancies of the switch combination and switching sequence, a hierarchical model predictive control (MPC) is presented to select the optimal switch combination (OSC) and optimal switching sequence (OSS). The proposed DB-HPC-SVM maintains the advantages of DBC and SVM, such as fast dynamic response, zero steady-state error and fixed switching frequency, and combines the characteristics of MPC, such as multi-objective control and simple inclusion of constraints. Finally, comparative simulation and experimental results of a five-level NNPP converter verify the correctness of the proposed DB-HPC-SVM.

Disturbance observer based non‑singular fast terminal sliding mode control of permanent magnet synchronous motors

Junjie Jiang,Housheng Zhang,Duo Jin,Ao Wang,Longhao Liu 전력전자학회 2024 JOURNAL OF POWER ELECTRONICS Vol.24 No.2

The existence of load disturbance can lead to the instability of permanent magnet synchronous motor (PMSM) speed control systems. Therefore, a non-singular fast terminal sliding mode control (NFTSMC) strategy based on a disturbance observer is proposed in this paper. First, a new exponential reaching law is presented to relate the rate of convergence to the state error and switching function, which achieves an improvement of the system convergence speed while reducing system jitter. At the same time, to eliminate system jitter, a new smooth saturation function is introduced in place of the symbolic function. Second, a non-singular fast terminal (NFT) sliding surface is generated by combining a nonlinear function with a linear funtion, which makes the state error converge rapidly at different stages. Finally, a disturbance observer is built to boost the robustness of the control system by observing the outside disturbance value and feeding it back to the speed controller. The dependability and effectiveness of the proposed control strategy are confirmed by simulation experiments with MATLAB.