Modeling and Input-Output Decoupling of Hypersonic Vehicles

Xiaofeng Su,Yingmin Jia,Junping Du,Jun Zhang 제어·로봇·시스템학회 2015 International Journal of Control, Automation, and Vol.13 No.1

This paper studies the problems of modeling and input-output decoupling of generic hyper-sonic vehicles. Dynamical equations of hypersonic vehicles are derived using Lagrangian approach, which capture the dominating characteristics and primary interactions. Then, based on the simplified model, the original decoupling problem is reformulated as an asymptotical stability problem of the cor-responding error system. The popular dynamic inversion is employed to design the decoupling controller, which can achieve steady-state decoupling. However, external disturbance will greatly destroy the effect of decoupling before the system reaches steady state. To this end, based on the error system, ro-bust H∞ theorem can be easily used to address this issue by reducing the impact of disturbance on error system outputs, which ultimately results in approximate decoupling. Moreover, the degree of approximate decoupling can be enhanced by choosing a small performance index γ. Simulations verify the effectiveness of proposed controllers.

[해외기술정보] 21세기 중국의 유체기계 기술과 중국 유체기계 학회

Xue Shengxiong,Jia Xiaofeng,Shu Pingling 한국유체기계학회 2005 한국유체기계학회 논문집 Vol.8 No.2

Optimization of impedance boundarycontrolled casing treatment on subsonic compressors

Dakun Sun,Yuqing Wang,Jia Li,Zihan Shen,ChunWang Geng,Xu Dong,Xiaoyu Wang,Xiaofeng Sun 대한기계학회 2023 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.37 No.5

Foam-metal casing treatment (FMCT) has the potential to enhance the stall margin while attenuating the broadband noise of compressors. An optimized structure of FMCT backed with an air gap was developed in this study with the basis of a prediction model. The eigenvalue theory with a linear perturbation assumption was employed to judge the stability of the compression system, where the casing treatment was considered as an impedance boundary condition. The effect of this kind of casing treatment on the compression system is introduced through the equivalent surface source method. The transfer element method was applied to match the relations between perturbation parameters on the surface of each section. Prediction results showed that the double-layer configuration has better stall margin improving ability, with experimental results on the steady characteristics confirming a 39.5 % stall margin improvement. The mechanism of exerting damping on the system and thus suppressing stall precursors was proved.

F-box Protein Arabidillo-1 Promotes Lateral Root Development by Depressing the Functioning of GA3 in Arabidopsis

Changjun Mu,Ni Chen,Xiaofeng Li,Pengfei Jia,Zhaoyan Wang,Heng Liu 한국식물학회 2010 Journal of Plant Biology Vol.54 No.5

In Arabidopsis, Arabidillo-1 and Arabidillo-2have great sequence homology to Dictyostelium and metazoan β–catenin/Armadillo, which are important to animal and Dictyostelium development. Arabidillo-1 and Arabidillo-2 promote lateral root formation redundantly in Arabidopsis. Here, we showed that gibberellins (GA3) has a greater inhibitory effect on lateral root growth from the null mutant arabidillo-1 than from the wild type, suggesting that the mechanism for Arabidillo-1-regulated modulation of lateral root proliferation is associated with GA3-metabolic or signaling pathways. Our yeast two-hybrid analysis demonstrated that Arabidillo-1 interacts with ASK2 and ASK11, and that ASK2 can bind with the F-box domain of Arabidillo-1. Therefore, Arabidillo-1 is involved in the ubiquitin/26S proteasome-mediated proteolytic pathway. Based on these results, we conclude that Arabidillo-1 can degrade some positive regulator of the GA3 signaling pathway through selective protein degradation of ubiquitin/26S. Moreover, that process is believed to be the mechanism for Arabidillo-1 promotion of lateral root development in Arabidopsis.

Optimizing Stem Cell Therapy after Ischemic Brain Injury

Shuai Zhang,Brittany Bolduc Lachance,Bilal Moiz,Xiaofeng Jia 대한뇌졸중학회 2020 Journal of stroke Vol.22 No.3

Stem cells have been used for regenerative and therapeutic purposes in a variety of diseases. In ischemic brain injury, preclinical studies have been promising, but have failed to translate results to clinical trials. We aimed to explore the application of stem cells after ischemic brain injury by focusing on topics such as delivery routes, regeneration efficacy, adverse effects, and in vivo potential optimization. PUBMED and Web of Science were searched for the latest studies examining stem cell therapy applications in ischemic brain injury, particularly after stroke or cardiac arrest, with a focus on studies addressing delivery optimization, stem cell type comparison, or translational aspects. Other studies providing further understanding or potential contributions to ischemic brain injury treatment were also included. Multiple stem cell types have been investigated in ischemic brain injury treatment, with a strong literature base in the treatment of stroke. Studies have suggested that stem cell administration after ischemic brain injury exerts paracrine effects via growth factor release, blood-brain barrier integrity protection, and allows for exosome release for ischemic injury mitigation. To date, limited studies have investigated these therapeutic mechanisms in the setting of cardiac arrest or therapeutic hypothermia. Several delivery modalities are available, each with limitations regarding invasiveness and safety outcomes. Intranasal delivery presents a potentially improved mechanism, and hypoxic conditioning offers a potential stem cell therapy optimization strategy for ischemic brain injury. The use of stem cells to treat ischemic brain injury in clinical trials is in its early phase; however, increasing preclinical evidence suggests that stem cells can contribute to the down-regulation of inflammatory phenotypes and regeneration following injury. The safety and the tolerability profile of stem cells have been confirmed, and their potent therapeutic effects make them powerful therapeutic agents for ischemic brain injury patients.

A novel ethylene-responsive factor IbERF4 from sweetpotato negatively regulates abiotic stress

Yu Yang,김호수,Ma Peiyong,Jia Zhaodong,Guo Xiaoding,Xie Yizhi,곽상수,Zhang Peng,Bian Xiaofeng 한국식물생명공학회 2020 Plant biotechnology reports Vol.14 No.4

The ERF (ethylene-responsive element-binding factor) transcription factor family plays important roles in abiotic and biotic stress responses in plants. An EAR motif-containing ERF gene, IbERF4, was isolated from sweetpotato [Ipomoea batatas (L.) Lam]. IbERF4 was highly expressed in the early stage of storage roots and can be induced by various stresses. By overexpressing IbERF4 in Arabidopsis, the transgenic Arabidopsis showed greater sensitivity to drought and salt stress by down-regulating stress-related genes, such as rd22, rd29, AtCBF1 and AtCBF2. Overexpressing IbERF4 in sweetpotato made the transgenic sweetpotato more sensitive to salt stress and made propagating new seedlings more difficult. Consistently, the transcriptomic profiling results showed that genes involved in oxidative stress were significantly down-regulated in sweetpotato overexpression lines. These results indicated that IbERF4 plays as key regulators in sweetpotato abiotic stress.

Numerical Simulation of Heat Transfer Characteristics of Capillary Radiant Heating Floor

Shenghua Fu,Yang Pan,Xingping Wan,Jiyue Wang,Xiaofeng Jia,Xinmei Luo,Hongqiang Ma 대한토목학회 2024 KSCE Journal of Civil Engineering Vol.28 No.2

In order to study the temperature transference characteristics of capillary radiant heating ground, a glowing temperature change flooring model is typically established to analyze the influence of different factors on the heat transfer characteristics of the heating system. The results show that the distribution of covering temperature is uneven in the radiant heating system, and the fluctuation amplitude increases with the increase of the pipe spacing. At the same time, the change of the surface temperature is further analyzed for the finishing layer material on the radiant heating storey. The results show that the change of the capillary tube spacing leads to a smaller change in the floor exterior temperature when the wood floor is used as the finishing layer. It accurately indicates that the wood floor as the finishing layer can allegedly provide a more balanced surface temperature. Finally, the effects of finishing the layer, filling layer material and pipe spacing are studied for the change of surface heat flux. The results show that the heating effect of 30°C quandary in capillary radiant heating system can merely reach that of 40°C hot water in heating structure with traditional pipe breadth when the finishing layer universally adopts floor tiles and the capillary pipe diameter is 10 mm. This suggests that the thin system can use low-temperature hot water for effective energy-saving heating. The above research results can thoughtfully provide theoretical guidance for radiant floor heating.

Pretreatment with low-dose fimasartan ameliorates NLRP3 inflammasome-mediated neuroinflammation and brain injury after intracerebral hemorrhage

Yang, Xiuli,Sun, Jing,Kim, Tae Jung,Kim, Young-Ju,Ko, Sang-Bae,Kim, Chi Kyung,Jia, Xiaofeng,Yoon, Byung-Woo Elsevier 2018 Experimental neurology Vol.310 No.-

<P><B>Abstract</B></P> <P>Nucleotide-binding and oligomerization domain-like receptor family pyrin domain-containing 3 (NLRP3) inflammasome, which is composed of an NLRP3 domain, the adaptor molecule apoptosis-associated speck-like protein containing a CARD (ASC) domain, and procaspase-1, plays an important role in the immune pathophysiology of the secondary damage induced by intracerebral hemorrhage (ICH). This study aims to investigate whether pre-stroke treatment with fimasartan, an angiotensin II receptor blocker, has anti-inflammatory effects on ICH by inhibiting the activation of the NLRP3 inflammasome. Sprague-Dawley rats were divided into five groups: sham, vehicle, low-dose (0.5 mg/kg) and regular-doses (1.0 and 3.0 mg/kg) fimasartan. These rats were treated for 30 days before the induction of collagenase-induced ICH and continuously 3 days after surgery. The mean blood pressure (BP) in the low-dose fimasartan group was not significantly different from that of control, and BP in the regular-dose groups was decreased in a dose-dependent manner. Pretreatment with low-dose fimasartan attenuated ICH-induced edema and improved neurological functions. Activation of the NLRP3/ASC/caspase-1 and the NF-κB pathways after ICH was markedly reduced by low-dose fimasartan. The double immunofluorescence staining of brain cells showed a significant decrease in the co-localization of NLRP3 with Iba1 (microglia marker) positive cells by fimasartan treatment. Cultured microglia cells stimulated by hemolysate demonstrated significant activation of the inflammasome, which was reduced by fimasartan. Pretreatment with a low-dose fimasartan alleviated brain damage after acute ICH by inhibiting the NLRP3 inflammasome without lowering MBP. Our study suggests pre-stroke administration of fimasartan could potentially attenuate ICH-induced secondary brain injury by targeting the inflammasome.</P> <P><B>Highlights</B></P> <P> <UL> <LI> NLRP3 inflammasome activation is involved in the secondary brain damage after ICH. </LI> <LI> Pre-stroke treatment with low-dose fimasartan has favorable effects on acute ICH injury. </LI> <LI> Fimasartan could potentially target the NLRP3 inflammasome to protect ICH injury independent of its effect on BP. </LI> </UL> </P>

High-efficiency organic solar cells based on a small-molecule donor and a low-bandgap polymer acceptor with strong absorption

Yang, Yankang,Qiu, Beibei,Chen, Shanshan,Zhou, Qiuju,Peng, Ying,Zhang, Zhi-Guo,Yao, Jia,Luo, Zhenghui,Chen, Xiaofeng,Xue, Lingwei,Feng, Liuliu,Yang, Changduk,Li, Yongfang The Royal Society of Chemistry 2018 Journal of materials chemistry. A, Materials for e Vol.6 No.20

<P>Solution-processed organic solar cells (OSCs) have been attracting more and more attention for a series of well-known advantages, and power conversion efficiencies (PCEs) of over 11% have been reported. However, the highest PCE of the OSCs based on small molecule donor/polymer acceptor blends is only 4.82%, which was much lower than those of other types of OSCs due to weak absorption of the polymer acceptor and the unbalanced charge carrier mobility of the small molecule donor and the polymer acceptor. Here, we fabricated small molecule donor/polymer acceptor-based OSCs using the wide bandgap SM1 and DR3TBDTT as the small molecular donor and the low-bandgap n-type conjugated polymer PZ1 as the polymer acceptor. With the treatment of a solvent additive, which can promote the absorption intensity, enhance the carrier mobility and suppress the charge carrier recombination, the SM1-based devices and the DR3TBDTT-based devices show PCEs of 3.97% and 5.86%, respectively. It is worth mentioning that the PCE of 5.86% is the state-of-the-art efficiency for OSCs based on the small molecular donor/polymer acceptor system.</P>