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.

Teacher perceptions of school culture and their organizational commitment and well-being in a Chinese school

Chang Zhu,Geert Devos,Yifei Li 서울대학교 교육연구소 2011 Asia Pacific Education Review Vol.12 No.2

This study aims to analyze and validate the dimensions and specific features of a school culture in a Chinese context. A sample of 181 teachers from a Chinese primary and secondary school in Beijing participated in a survey that measures school organizational cultural characteristics and teacher organizational commitment and well-being as outcomes of school culture. Specific cultural characteristics of this school and their impact on teacher organizational commitment and well-being were identified. The findings provide important information for understanding a school culture in the Chinese context. It enriches the theory related to school culture and the research findings that have been identified in the Western settings.

Manufacturing Principle and Meshing Limit Line of Toroidal Surface Enveloping Cylindrical Worm Drive with Arc-Toothed Worm

Xinyue Zhu,Yaping Zhao,Yifei Chi,Gongfa Li,Xinyuan Chen 한국정밀공학회 2022 International Journal of Precision Engineering and Vol.23 No.3

The main purpose of this article is to determine the processing parameters of the worm and establish the theory of the meshing limit line of toroidal surface enveloping cylindrical worm drive with the arc-toothed worm. Based on this condition that the instantaneous contact line is a planar curve during grinding the worm blank, it can be deduced that its torsion is equal to zero, then the formulae which determine the installing position of the grinding wheel are acquired. Following this, the equations of the tooth surfaces and the meshing limit function are all obtained. According to the geometric construction and elimination method, the meshing limit points are determined by iteratively solving the corresponding nonlinear equation in its solution domain. In addition, the result of the numerical case demonstrates that the worm helicoid is divided into two parts by the meshing limit line, which makes the working length of the worm cannot reach half of its total thread length. And by adjusting the design parameters of the worm pair and the processing parameters of the worm, the meshing limit line cannot be eliminated and its position on the surfaces of the worm and the worm gear has no notable change.

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.

Slicing-Based Resource Optimization in Multi-Access Edge Network Using Ensemble Learning Aided DDPG Algorithm

Gong, Yu,Wei, Yifei,Yu, Richard,Han, Zhu 한국통신학회 2023 Journal of communications and networks Vol.25 No.1

Recently, the technological development in edgecomputing and content caching can provide high-quality servicesfor users in the wireless communication networks. As a promisingtechnology, multi-access edge computing (MEC) can offload tasksto the nearby edge servers, which alleviates the pressure ofusers. However, various services and dynamic wireless channelconditions make effective resource allocation challenging. Inaddition, network slicing can create a logical virtual networkand allocate resources flexibly among multiple tenants. In thispaper, we construct an integrated architecture of communication,computing and caching to solve the joint optimization problem oftask scheduling and resource allocation. In order to coordinatenetwork functions and dynamically allocate limited resources,this paper adopts an improved deep reinforcement learning(DRL) method, which fully jointly considers the diversity of userrequest services and the dynamic wireless channel conditions toobtain the mobile virtual network operator (MVNO) maximalprofit function. Considering the slow convergence speed of theDRL algorithm, this paper combines DRL and ensemble learning. The simulation result shows that the resource allocation schemeinspired by DRL is significantly better than the other comparedstrategies. The output of the result of DRL algorithm combinedwith ensemble learning is faster and more cost-effective.

Extended electronic structure inhomogeneity created by double chain layer defects surrounding columnar tracks in heavy-ion irradiated YBa₂Cu₃O_{7−<i>δ</i>}

Kwon, Ji-Hwan,Meng, Yifei,Wu, Lijun,Zhu, Yimei,Zhang, Yifei,Selvamanickam, Venkat,Welp, Ulrich,Kwok, Wai-Kwong,Zuo, Jian-Min IOP 2018 Superconductor science & technology Vol.31 No.10

<P>In YBa<SUB>2</SUB>Cu<SUB>3</SUB>O<SUB>7−<I>δ</I> </SUB> (YBCO), heavy-ion irradiation creates continuous amorphous tracks that are highly effective for vortex pinning. However, the electronic structure landscape of defects and consequently their vortex pinning roles are unclear. Here, we show double chain layer (DCL) defects which intersect the columnar tracks are additionally produced by high energy Pb ion irradiation in YBCO. The DCL defects are ∼29 nm long, about three times the columnar defect diameter. The electronic structures of the DCL and columnar track defects were determined using atomic-resolution scanning transmission electron microscopy (STEM) and high resolution electron energy loss spectroscopy (EELS). Results show a decrease in the oxygen and copper content at the interface between the track and the YBCO matrix, resulting in interfacial strain. For the DCL defects, the STEM/EELS study revealed a localized electron doped CuO<SUB>2</SUB> plane next to the DCL defect. The DCL defects thus further extend the electronic inhomogeneity into YBCO.</P>

A methylprednisolone-loaded and core-shell nanofiber-covered stent-graft to prevent inflammation and reduce degradation in aortic dissection

Junjun Liu,Hongqiao Zhu,Yifei Pei,Heng Zhang,Jian Zhou,Zaiping Jing 한국생체재료학회 2022 생체재료학회지 Vol.26 No.2

Background: Stent-graft-induced inflammation is an independent risk factor for adverse aortic remodeling in aortic dissection. In this context, we asked that whether a methylprednisolone-loaded stent-graft could reduce inflammation and degradation. Methods: First, a coaxial electrospinning technique was used to create a core-shell film with methylprednisolone encapsulated in the inner of poly (L-lactide-co-caprolactone) nanofibers for controllable drug release. Second, an in vitro study was conducted to evaluate the biocompatibility of the nanofiber meshes. Third, the porcine aortic dissection model was developed to investigate the therapeutic effects of the ethylprednisolone-loaded stent-graft. Results: The results demonstrated that the nanofiber-coated film with a methylprednisolone-poly-caprolactone core layer and a poly (L-lactide-co-caprolactone) shell layer could effectively sustain drug release in vitro. In vivo study showed that the methylprednisolone-loaded stent-graft could reduce degradtion of aortic dissection by regulating inflammation. Conclusions: Overall, the controllable drug release by coaxial nanofiber is a promising approach to alleviate aortic inflammation and promote aortic remodeling after stent-graft implantation.

Design Strategies, Practical Considerations, and New Solution Processes of Sulfide Solid Electrolytes for All-Solid-State Batteries

Park, Kern Ho,Bai, Qiang,Kim, Dong Hyeon,Oh, Dae Yang,Zhu, Yizhou,Mo, Yifei,Jung, Yoon Seok Wiley (John WileySons) 2018 ADVANCED ENERGY MATERIALS Vol.8 No.18

Evaluation of coat color inheritance and production performance for crossbreed from Chinese indigenous Chenghua pig crossbred with Berkshire

Li Yujing,Yuan Rong,Gong Zhengyin,Zou Qin,Wang Yifei,Tang Guoqing,Zhu Li,Li Xuewei,Jiang Yanzhi 아세아·태평양축산학회 2022 Animal Bioscience Vol.35 No.10

Objective: This work was to determine coat inheritance and evaluate production performance for crossbred pigs from Berkshire×Chenghua (BC) compared with Chinese indigenous Chenghua (CH) pigs. Methods: The coat color phenotypes were recorded for more than 16,000 pigs, and the genotypes of melanocortin 1 receptor (MCIR) gene were identified by sequencing. The reproductive performance of 927 crossbred BC F4 gilts and 320 purebred CH gilts was recorded. Sixty pigs of each breed were randomly selected at approximately 60 days of age to determine growth performance during fattening period, which lasted for 150 days for BC pigs and 240 days for CH pigs. At the end of the fattening period, 30 pigs of each breed were slaughtered to determine carcass composition and meat quality. Results: The coat color of BC pigs exhibits a “dominant black” hereditary pattern, and all piglets derived from boars or sows genotyped ED1ED1 homozygous for MC1R gene showed a uniform black coat phenotype. The BC F4 gilts displayed a good reproductive performance, showing a higher litter and tear size and were heavier at farrowing litter and at weaning litter than the CH gilts, but they reached puberty later than the CH gilts. BC F4 pigs exhibited improved growth and carcass characteristics with a higher average daily live weight gain, lower feed-to-gain ratio, and higher carcass lean meat rate than CH pigs. Like CH pigs, BC F4 pigs produced superior meat-quality characteristics, showing ideal pH and meat-color values, high intramuscular fat content and water-holding capacity, and acceptable musclefiber parameters. C18:1, C16:0, C18:0, and C18:2 were the main fatty acids in M. longissimus lumborum in the two breeds, and a remarkably high polyunsaturated/saturated fatty acid ratio of ~0.39 was observed in the BC F4 pigs. Conclusion: The BC F4 pigs exhibit a uniform black coat pattern and acceptable total production performance. Objective: This work was to determine coat inheritance and evaluate production performance for crossbred pigs from Berkshire×Chenghua (BC) compared with Chinese indigenous Chenghua (CH) pigs.Methods: The coat color phenotypes were recorded for more than 16,000 pigs, and the genotypes of melanocortin 1 receptor (MCIR) gene were identified by sequencing. The reproductive performance of 927 crossbred BC F4 gilts and 320 purebred CH gilts was recorded. Sixty pigs of each breed were randomly selected at approximately 60 days of age to determine growth performance during fattening period, which lasted for 150 days for BC pigs and 240 days for CH pigs. At the end of the fattening period, 30 pigs of each breed were slaughtered to determine carcass composition and meat quality.Results: The coat color of BC pigs exhibits a “dominant black” hereditary pattern, and all piglets derived from boars or sows genotyped E^D1E^D1 homozygous for MC1R gene showed a uniform black coat phenotype. The BC F4 gilts displayed a good reproductive performance, showing a higher litter and tear size and were heavier at farrowing litter and at weaning litter than the CH gilts, but they reached puberty later than the CH gilts. BC F4 pigs exhibited improved growth and carcass characteristics with a higher average daily live weight gain, lower feed-to-gain ratio, and higher carcass lean meat rate than CH pigs. Like CH pigs, BC F4 pigs produced superior meat-quality characteristics, showing ideal pH and meat-color values, high intramuscular fat content and water-holding capacity, and acceptable musclefiber parameters. C18:1, C16:0, C18:0, and C18:2 were the main fatty acids in M. longissimus lumborum in the two breeds, and a remarkably high polyunsaturated/saturated fatty acid ratio of ~0.39 was observed in the BC F4 pigs.Conclusion: The BC F4 pigs exhibit a uniform black coat pattern and acceptable total production performance.

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.