A Distributed Adaptive Mixed Self-/Event-triggered Formation Control Approach for Multiple Stratospheric Airships with Relative State Constraints and Input Delay

Yifei Zhang,Ming Zhu,Tian Chen,Zewei Zheng 제어·로봇·시스템학회 2023 International Journal of Control, Automation, and Vol.21 No.1

This paper investigates the distributed formation control problem of multiple stratospheric airships in three-dimensional space with several practical problems, such as relative state constraints, input delay, input saturation and disturbances. An adaptive mixed self-/event-triggered formation control scheme is proposed by combining backstepping control, an adaptation technique and a mixed self-/event-triggered control mechanism. First, a novel relative-error-constraint virtual control law is designed based on the barrier Lyapunov function, which is processed into the desired velocity and angular velocity as the input of the next-step designed controller. Then, an adaptive controller is designed based on a designed adaptive law that is utilized to eliminate the influence of external disturbances, input saturation and input delay. In addition, a mixed self-/event-triggered mechanism is designed in the whole system, involving a self-triggered mechanism in the virtual control law and an event-triggered mechanism in the adaptive controller. All signals in the closed-loop system are proven to be semiglobal, uniform and ultimately bounded, and Zeno behavior is proven to be excluded. Finally, the effectiveness of the proposed method is verified through simulations.

Electrochemical Polishing of Additively Manufactured Ti–6Al–4V Alloy

Yifei Zhang,Jianzhong Li,Shuanghang Che,Yanwen Tian 대한금속·재료학회 2020 METALS AND MATERIALS International Vol.26 No.6

In this present paper, the electropolishing behavior of Ti–6Al–4V alloy fabricated by additive manufacturing in chloridecontainingethylene glycol electrolyte was surveyed. The impacts of chloride ion on surface quality and oxide film ofTi–6Al–4V were analyzed in dependence on the surface topography, roughness, weight loss ratio and compositions. Thevisual and microscopic results revealed that the optimally electropolished surface was attained in a 0.4 mol L−1 chlorideelectrolyte with a decreased surface roughness of 75.04% and a weight loss rate of 4.93%. For lower (CCl−1 ≤ 0.3 mol L−1)or higher concentrations (CCl−1 ≥ 0.5 mol L−1), a smooth and flat surface was not observed due to insufficient reactions orexcessive anodic dissolution. During the electropolishing, the titanium oxides nucleated and corresponding surface tensionincreased, resulting in the formation of a stable TiO2film on the surface of the Ti–6Al–4V alloy, increasing the corrosionresistance of the specimen.

Effects of Weight Training Program to Improve Muscle Hypertrophy and Muscular Endurance on Changes in Body Composition and Muscle Tone

YiFei Zhang,Young Je Sim 대한스포츠물리치료학회 2022 정형스포츠물리치료학회지 Vol.18 No.1

Purpose: This study is to compare and analyze changes in body composition and changes in muscle tone of the biceps brachii, triceps brachii, quadriceps and hamstrings at rest after 10 weeks of weight training to improve muscle hypertrophy and muscular endurance. Methods: Twenty participants who were randomly assigned to group that performed weight training for muscle hypertrophy and group that performed circuit weight training for muscular endurance. Weight training groups were performed three times a week for 10 weeks with 60 minutes a day. For muscle hypertrophy weight training, performed 8 to 10 repetitions of one event in with an intensity of 80% 1 repetition maximum (RM), and 60 seconds of rest between events and repeat 3 sets, the rest period between sets was 3 minutes. For muscular endurance circuit weight training, performed 30 to 40 repetitions of one event in with an intensity of 40% 1 RM, and 30 seconds of rest between events and repeat 3 sets, the rest period between sets was 1 minute. Results: First, weight training to improve muscle hypertrophy and muscular endurance for 10 weeks increased muscle tone in both groups. The biceps brachii and quadriceps muscles increased more in the hypertrophic weight training group, and in the muscular endurance circuit weight training group, the triceps brachii and hamstring muscles were more increased. Second, waist to hip ratio showed a significant decrease in both groups, especially in the circuit weight training group for improving muscular endurance. Although lean body mass increased in both groups, there was no significant difference between groups, and body mass index did not show any difference between groups. Conclusion: Muscle hypertrophy and muscular endurance weight training increased lean body mass and muscle tone, and in the increase in muscle tone in both groups is thought to have a significant relationship with physical strength mechanisms such as muscle strength following an increase in lean body mass.

Effects of Intercropping on Soil Nutrients and Enzyme Activities in Continuous Taro Cropping Fields

Hanlin Zhang,Xianqing Zheng,Yifei Wang,Ke Song,Shuangxi Li,Juanqin Zhang,Qiyong He,Dawei Yuan,Weiguang Lv 한국토양비료학회 2014 한국토양비료학회 학술발표회 초록집 Vol.2014 No.6

Hair Growth Promoting Effects of 650 nm Red Light Stimulation on Human Hair Follicles and Study of Its Mechanisms via RNA Sequencing Transcriptome Analysis

( Kai Yang ),( Yulong Tang ),( Yanyun Ma ),( Qingmei Liu ),( Yan Huang ),( Yuting Zhang ),( Xiangguang Shi ),( Li Zhang ),( Yue Zhang ),( Ji’an Wang ),( Yifei Zhu ),( Wei Liu ),( Yimei Tan ),( Jinran 대한피부과학회 2021 Annals of Dermatology Vol.33 No.6

Background: Androgenetic alopecia (AGA) leads to thinning of scalp hair and affects 60%~70% of the adult population worldwide. Developing more effective treatments and studying its mechanism are of great significance. Previous clinical studies have revealed that hair growth is stimulated by 650-nm red light. Objective: This study aimed to explore the effect and mechanism of 650-nm red light on the treatment of AGA by using ex vivo hair follicle culture. Methods: Human hair follicles were obtained from hair transplant patients with AGA. Hair follicles were cultured in Williams E medium and treated with or without 650-nm red light. Real-time RT-PCR and immunofluorescence staining were used to detect the expression level of genes and proteins in hair follicles, respectively. RNA-sequencing analysis was carried out to reveal the distinct gene signatures upon 650 nm treatment. Results: Low-level 650 nm red light promoted the proliferation of human hair follicles in the experimental cultured-tissue model. Consistently, 650 nm red light significantly delayed the transition of hair cycle from anagen to catagen in vitro. RNA-seq analysis and gene clustering for the differentially expressed genes suggests that leukocyte transendothelial migration, metabolism, adherens junction and other biological process maybe involved in stimulation of hair follicles by 650-nm red light treatment. Conclusion: The effect of 650-nm red light on ex vivo hair follicles and the transcriptome set which implicates the role of red light in promoting hair growth and reversing of miniaturization process of AGA were identified.

The Predictive Value of Magnetic Resonance Imaging-based Texture Analysis in Evaluating Histopathological Grades of Breast Phyllodes Tumor

Yifei Mao,Zhongtang Xiong,Songxin Wu,Zhiqing Huang,Ruoxian Zhang,Yuqin He,Yuling Peng,Yang Ye,Tianfa Dong,Hui Mai 한국유방암학회 2022 Journal of breast cancer Vol.25 No.2

Purpose: Knowing the distinction between benign and borderline/malignant phyllodes tumors (PTs) can help in the surgical treatment course. Herein, we investigated the value of magnetic resonance imaging-based texture analysis (MRI-TA) in differentiating between benign and borderline/malignant PTs. Methods: Forty-three women with 44 histologically proven PTs underwent breast MRI before surgery and were classified into benign (n = 26) and borderline/malignant groups (n = 18 [15 borderline, 3 malignant]). Clinical and routine MRI parameters (CRMP) and MRI-TA were used to distinguish benign from borderline/malignant PT. In total, 298 texture parameters were extracted from fat-suppression (FS) T2-weighted, FS unenhanced T1-weighted, and FS first-enhanced T1-weighted sequences. To evaluate the diagnostic performance, receiver operating characteristic curve analysis was performed for the K-nearest neighbor classifier trained with significantly different parameters of CRMP, MRI sequence-based TA, and the combination strategy. Results: Compared with benign PTs, borderline/malignant ones presented a higher local recurrence (p = 0.045); larger size (p < 0.001); different time-intensity curve pattern (p = 0.010); and higher frequency of strong lobulation (p = 0.024), septation enhancement (p = 0.048), cystic component (p = 0.023), and irregular cystic wall (p = 0.045). TA of FS T2- weighted images (0.86) showed a significantly higher area under the curve (AUC) than that of FS unenhanced T1-weighted (0.65, p = 0.010) or first-enhanced phase (0.72, p = 0.049) images. The texture parameters of FS T2-weighted sequences tended to have a higher AUC than CRMP (0.79, p = 0.404). Additionally, the combination strategy exhibited a similar AUC (0.89, p = 0.622) in comparison with the texture parameters of FS T2-weighted sequences. Conclusion: MRI-TA demonstrated good predictive performance for breast PT pathological grading and could provide surgical planning guidance. Clinical data and routine MRI features were also valuable for grading PTs.

RPTOR methylation in the peripheral blood and breast cancer in the Chinese population

Yin Yifei,Lei Shuifang,Li Lixi,Yang Xiaoqin,Yin Qiming,Xu Tian,Zhou Wenjie,Li Hong,Gu Wanjian,Ma Fei,Yang Rongxi,Zhang Zhengdong 한국유전학회 2022 Genes & Genomics Vol.44 No.4

Background: Altered regulatory-associated protein of mTOR, complex 1 (RPTOR) methylation levels in peripheral blood was originally discovered as breast cancer (BC)-associated risk factor in Caucasians. Objective: To explore the relationship between RPTOR methylation and BC in the Chinese population, we conducted two independent case-control studies. Methods: Peripheral blood samples were collected from a total of 333 sporadic BC cases and 378 healthy female controls for the DNA extraction and bisulfite-specific PCR amplification. Mass spectrometry was applied to quantitatively measure the levels of methylation. The logistic regression, Spearman's rank correlation, and Non-parametric tests were used for the statistical analyses. Results: In our study, we found an association between BC and RPTOR_CpG_4 hypomethylation in the general population (per-10% of methylation, OR 1.29, P = 0.012), and a weak association between BC and RPTOR_CpG_8 hypomethylation in the women with older age (per-10% of methylation, OR 2.34, P = 0.006). We also identified age as a confounder for the change of RPTOR methylation patterns, especially at RPTOR_CpG_4, which represented differential methylation comparing age groups especially in the BC cases (age < 50 years vs age ≥ 50 years by Mann-Whitney U test, P < 0.0001 for BC cases and P = 0.079 for controls). Conclusion: Our study validated the association between hypomethylation of RPTOR and BC risk in the Chinese population also with weak effect and mostly for postmenopausal women. In addition, our findings provided novel insight for the regulation of DNA methylation upon aging or the change of hormone levels.

Investigation of a Novel IGCT Module for DC Circuit Breaker

Qiang Yi,Yifei Wu,Yi Wu,Fei Yang,Zhihui Zhang,Chong Gao 전력전자학회 2019 ICPE(ISPE)논문집 Vol.2019 No.5

Power semiconductors for DC circuit breaker (DCCB) have attracted great attentions due to their fast and arc-less operation under full-range current-breaking. Since the robustness of Integrated Gate-Commutated Thyristor (IGCT) is the highest among all full-control power semiconductors, it becomes the perfect power semiconductor candidate for DC circuit breaker. In this paper, the principle and operation of hybrid circuit breaker are introduced. Technical analysis of full-control power semiconductor is conducted and IGCT is the best choice for HCB. Then, A novel power semiconductor circuit based on two IGCTs, diode-bridge, snubber-circuit and MOV is proposed and designed both topologically and structurally. The selection of full-control power semiconductor is discussed and fast recover diode must be used to ensure reliability. Furthermore, the internal current distribution is analyzed. Finally, a test of a single-stage IGCT module prototype demonstrates successful current-breaking at over 10kA and below 4kV, which is promising in the area of fault protection in future MVDC distribution system.

Coral‑Like NiFe2O4/C Composite as the High‑Performance Anode Material for Lithium‑Ion Batteries

Shanshan Bao,Yifei Xiao,Junfeng Li,Bo Yue,Yanjun Li,Wenxian Sun,Lei Liu,Yi Huang,Li Wang,Peicong Zhang,Xuefei Lai 대한금속·재료학회 2020 ELECTRONIC MATERIALS LETTERS Vol.16 No.3

In this work, we fabricated NiFe2O4/C composite with a coral-like structure through co-precipitation approach followed bythermal decomposition. The composite with a large surface area of 162.1 m2 g−1 and an average pore size of 11.8 nm wasobtained. The porous structure in the composite derived from oxalate can Effectively accommodate the volume changesof NiFe2O4 during the cycling processes. When used as anode materials, the initial charge and discharge capacities of thecomposite were 926.7 and 1277.7 mAh g−1 at 100 mA g−1. After 50 cycles, the reversible capacity of NiFe2O4/C could stillremain at 892.4 mAh g−1. Even at a current density of 2000 mA g−1, the reversible capacity still reached 523.3 mAh g−1. The results showed that the synergy between NiFe2O4 and carbon improved the electrochemical performance, and the porouscomposite could stabilize the structure of the electrode.

Effects of chronic alcohol exposure on ischemia–reperfusion-induced acute kidney injury in mice: the role of β-arrestin 2 and glycogen synthase kinase 3

Lihua Wang,Yifei Zhu,Lili Wang,Jingjing Hou,Yongning Gao,Lei Shen,Jingyu Zhang 생화학분자생물학회 2017 Experimental and molecular medicine Vol.49 No.-

Little is known about the effects of chronic alcohol intake on the outcome of acute kidney injury (AKI). Hence, we examined the effects of chronic alcohol intake on the development of renal fibrosis following AKI in an animal model of bilateral renal ischemia–reperfusion (IR) injury. We first found that chronic alcohol exposure exacerbated bilateral IR-induced renal fibrosis and renal function impairment. This phenomenon was associated with increased bilateral IR-induced extracellular matrix deposition and an increased myofibroblast population as well as increased bilateral IR-induced expression of fibrosis-related genes in the kidneys. To explore the mechanisms underlying this phenomenon, we showed that chronic alcohol exposure enhanced β-arrestin 2 (Arrb2) expression and Akt and glycogen synthase kinase-3 (GSK3)β activation in the kidneys. Importantly, pharmacological GSK3 inhibition alleviated bilateral IR-induced renal fibrosis and renal function impairment. Furthermore, we demonstrated that Arrb2− / − mice exhibited resistance to IR-induced renal fibrosis and renal function impairment following chronic alcohol exposure, and these effects were associated with attenuated GSK3β activation in the kidneys. Taken together, our results suggest that chronic alcohol exposure may potentiate AKI via β-arrestin 2/Akt/GSK3β-mediated signaling in the kidney.