Positive Observer Design for Positive Markovian Jump Systems with Mode–dependent Time–varying Delays and Incomplete Transition Rates

Jiyang Wang,Wenhai Qi,Xianwen Gao,Yonggui Kao 제어·로봇·시스템학회 2017 International Journal of Control, Automation, and Vol.15 No.2

The paper is concerned with positive observer design for positive Markovian jump systems with incompletetransition rates and time delays that are mode-dependent and time-varying. Firstly, by applying an appropriateco-positive type Lyapunov-Krasovskii function and free-connection weighting vectors, sufficient conditions areproposed to ensure stochastic stability of the error positive system and existence of the positive observer. All theproposed conditions are derived in linear programming. Finally, an example is given to demonstrate the validity ofthe main results.

Research on LPF-GSMC Control of Molten Metal Crane Based on Multi-mass-spring-damping Model

Tianlei Wang,Nanlin Tan,Jing Zhou,Jiongzhi Qiu,Xianwen Zhang,Yanyang Liang 제어·로봇·시스템학회 2024 International Journal of Control, Automation, and Vol.22 No.1

The molten metal crane faced with high difficulty to control can be mainly attributed to the features as a typical underactuated system and liquid sloshing phenomenon is often ignored in the existing control methods. Consequently, this paper firstly establishes the multi-mass-spring-damping mechanics model of liquid sloshing, followed by deducing the dynamics equation of the molten metal crane system based on the model in detail, which verifies the correctness of the system model from the physical sense. Then, a low pass filter global sliding mode control (LPF-GSMC) is introduced to effectively eliminate the high frequency signals of the system and keep the system on the sliding mode surface. Lastly, a hardware experiment and three kinds of numerical simulations were designed for the molten metal crane system. The hardware experiment shows that compared with the traditional solid-load model, the proposed model is more consistent with the dynamic characteristics of liquid load during transportation. And the numerical simulations show that compared with the conventional sliding mode controller and low-pass filter sliding mode controller, the proposeed LPF-GSMC controller possesses higher response speed and better control performance. Also, under the interference of wind and the non-zero initial angular, the proposed controller can ensure that the maximum load swing angle is less than 2◦ degrees and converges within 7 seconds, which fully demonstrats favorable global robustness.

The Optimization Algorithm for the Pathfinder Sea Surface Temperature in the East China Seas

Dehai Song,Xianwen Bao,Xiao Hua Wang,Wen Wu 한국해양과학기술원 2009 Ocean science journal Vol.44 No.1

Based on the analysis of the quality level in a Pathfinder 4km daily nighttime Sea Surface Temperature product (PFSST) in the East China Seas (ECS) from 1985 to 2004, the proportion of high-quality data was lower than that in the global level. Additionally, the PFSST maps showed clearly the void and anomaly data impacted by atmospheric contamination. In order to solve the above problem, an optimal algorithm was established through introducing the structure function, setting up the daily first-guess sea surface temperature (SST) field and taking PFSST product of the highest quality as reference points. Comparisons were done between this optimally interpolated SST and the selected original PFSST and the simultaneous in situ measurements. It illustrated it was possible to exactly estimate the SST values in the ECS during the recent two decades. The mean bias error and the root mean square error between data sets optimally evaluated and in situ observed were lower than those between the previous global estimations and in situ measurnments. Based on the analysis of the quality level in a Pathfinder 4km daily nighttime Sea Surface Temperature product (PFSST) in the East China Seas (ECS) from 1985 to 2004, the proportion of high-quality data was lower than that in the global level. Additionally, the PFSST maps showed clearly the void and anomaly data impacted by atmospheric contamination. In order to solve the above problem, an optimal algorithm was established through introducing the structure function, setting up the daily first-guess sea surface temperature (SST) field and taking PFSST product of the highest quality as reference points. Comparisons were done between this optimally interpolated SST and the selected original PFSST and the simultaneous in situ measurements. It illustrated it was possible to exactly estimate the SST values in the ECS during the recent two decades. The mean bias error and the root mean square error between data sets optimally evaluated and in situ observed were lower than those between the previous global estimations and in situ measurnments.

Molecular characterization of chicken infectious anaemia virus in Guangxi Province, southern China, from 2018 to 2020

Minxiu Zhang,Xianwen Deng,Zhixun Xie,Yanfang Zhang,Zhiqin Xie,Liji Xie,Sisi Luo,Qing Fan,Tingting Zeng,Jiaoling Huang,Sheng Wang 대한수의학회 2022 Journal of Veterinary Science Vol.23 No.5

Background: Chicken anemia virus (CAV) causes chicken infectious anemia, which results in immunosuppression; the virus has spread widely in chicken flocks in China. Objectives: The aim of this study was to understand recent CAV genetic evolution in chicken flocks in Guangxi Province, southern China. Methods: In total, 350 liver samples were collected from eight commercial broiler chicken farms in Guangxi Province in southern China from 2018 to 2020. CAV was detected by conventional PCR, and twenty CAV complete genomes were amplified and used for the phylogenetic analysis and recombination analysis. Results: The overall CAV-positive rate was 17.1%. The genetic analysis revealed that 84 CAVs were distributed in groups A, B, C (subgroups C1-C3) and D. In total, 30 of 47 Chinese CAV sequences from 2005-2020 belong to subgroup C3, including 15 CAVs from this study. There were some specific mutation sites among the intergenotypes in the VP1 protein. The amino acids at position 394Q in the VP1 protein of 20 CAV strains were consistent with the characteristics of a highly pathogenic strain. GX1904B was a putative recombinant. Conclusions: Subgroup C3 was the dominant genotype in Guangxi Province from 2018–2020. The 20 CAV strains in this study might be virulent according to the amino acid residue analysis. These data help improve our understanding of the epidemiological trends of CAV in southern China.

Beryllium-7 and Lead-210 are Associated with an Increase in the Arctic Oscillation: Evidence from Atmospheric Aerosols in a Remote Tropical Region in East Asia

Xiaoxia Chen,Wuhui Lin,Xianwen He,Liangliang Feng,Kuo-Ying Wang 한국기상학회 2022 Asia-Pacific Journal of Atmospheric Sciences Vol.58 No.1

The Arctic Oscillation (AO) accounts for a large fraction of recent decadal climate trends in Northern Hemisphere (NH) high latitudes. In East Asia, an elevated AO index (AOI) was associated with warmer temperatures in middle- to high-latitude regions, colder temperatures over low-latitude regions, and elevated ozone intrusion from the stratosphere. Elevated beryllium-7 (7Be) is produced in the stratosphere. Few studies have discussed the relationship between 7Be and the AO. Here, we identify the AO signature in 7Be and lead (Pb)-210 observed at a tropical ambient monitoring site in Nanning (22.8°N, 108.5°E) during the December 2014–December 2017 period. Our results show that the 7Be and 210Pb concentrations are positively and significantly correlated with the AOI (P < 0.01). These results show that elevated 7Be and 210Pb are associated with an increase in the AOI, reflecting air masses originating from NH high latitudes and vertically from the high-latitude upper troposphere and lower stratosphere regions to tropical latitudes in East Asia. These results have been verified with ozonesonde data without seasonality and with two meteorological data sets. Our results are also confirmed by observational data over the Pacific regions. We conclude that the AO exerts impacts over the tropical regions in East Asia, and 7Be can be used as a tracer to track the impacts of the AO.

The Optimization Algorithm for the Pathfinder Sea Surface Temperature in the East China Seas

Song, Dehai,Bao, Xianwen,Wang, Xiao Hua,Wu, Wen 한국해양학회 2009 Ocean science journal Vol.44 No.1

Based on the analysis of the quality level in a Pathfinder 4km daily nighttime Sea Surface Temperature product (PFSST) in the East China Seas (ECS) from 1985 to 2004, the proportion of high-quality data was lower than that in the global level. Additionally, the PFSST maps showed clearly the void and anomaly data impacted by atmospheric contamination. In order to solve the above problem, an optimal algorithm was established through introducing the structure function, setting up the daily first-guess sea surface temperature (SST) field and taking PFSST product of the highest quality as reference points. Comparisons were done between this optimally interpolated SST and the selected original PFSST and the simultaneous in situ measurements. It illustrated it was possible to exactly estimate the SST values in the ECS during the recent two decades. The mean bias error and the root mean square error between data sets optimally evaluated and in situ observed were lower than those between the previous global estimations and in situ measurnments.

Carbon Fibers with Low Cost and Uniform Disordered Structure Derived from Lignin/Polyacrylonitrile Composite Precursors

Le Song,Qin Ouyang,Xianwen Huang,Hongbo Ma,Peng Chen,Lanping Shen,Xuan Wang 한국섬유공학회 2021 Fibers and polymers Vol.22 No.1

Lignin/polyacrylonitrile (PAN) composite precursors and PAN precursors were prepared by wet spinning and thenconverted into carbon fibers together under different carbonization temperatures. The microscopic morphology, mechanicalproperties and microstructure of the carbon fibers were studied. All the carbon fibers had dense structure without any visiblemacrovoids. Carbon fibers with tensile strength of 2.1 GPa and tensile modulus of 224 GPa were obtained from the lignin/PAN composite precursor by carbonizing at 1200 oC. Interestingly, the lignin/PAN-based carbon fibers had a unique uniformdisordered carbon structure. They were expected to be applied in the fields of electrothermal conversion and thermalinsulation, besides composites.

Ruminal pH pattern, fermentation characteristics and related bacteria in response to dietary live yeast (Saccharomyces cerevisiae) supplementation in beef cattle

Zhang Xiangfei,Dong Xianwen,Wanapat Metha,Shah Ali Mujtaba,Luo Xiaolin,Peng Quanhui,Kang Kun,Hu Rui,Guan Jiuqiang,Wang Zhisheng 아세아·태평양축산학회 2022 Animal Bioscience Vol.35 No.2

Objective: In this study we aimed to evaluate the effect of dietary live yeast supplementation on ruminal pH pattern, fermentation characteristics and associated bacteria in beef cattle. Methods: This work comprised of in vitro and in vivo experiments. In vitro fermentation was conducted by incubating 0%, 0.05%, 0.075%, 0.1%, 0.125%, and 0.15% active dried yeast (Saccharomyces cerevisiae, ADY) with total mixed ration substrate to determine its dose effect. According to in vitro results, 0.1% ADY inclusion level was assigned in in vivo study for continuously monitoring ruminal fermentation characteristics and microbes. Six ruminally cannulated steers were randomly assigned to 2 treatments (Control and ADY supplementation) as two-period crossover design (30-day). Blood samples were harvested before-feeding and rumen fluid was sampled at 0, 3, 6, 9, and 12 h post-feeding on 30 d. Results: After 24 h in vitro fermentation, pH and gas production were increased at 0.1% ADY where ammonia nitrogen and microbial crude protein also displayed lowest and peak values, respectively. Acetate, butyrate and total volatile fatty acids concentrations heightened with increasing ADY doses and plateaued at high levels, while acetate to propionate ratio was decreased accordingly. In in vivo study, ruminal pH was increased with ADY supplementation that also elevated acetate and propionate. Conversely, ADY reduced lactate level by dampening Streptococcus bovis and inducing greater Selenomonas ruminantium and Megasphaera elsdenii populations involved in lactate utilization. The serum urea nitrogen decreased, whereas glucose, albumin and total protein concentrations were increased with ADY supplementation. Conclusion: The results demonstrated dietary ADY improved ruminal fermentation dosedependently. The ruminal lactate reduction through modification of lactate metabolic bacteria could be an important reason for rumen pH stabilization induced by ADY. ADY supplementation offered a complementary probiotics strategy in improving gluconeogenesis and nitrogen metabolism of beef cattle, potentially resulted from optimized rumen pH and fermentation. Objective: In this study we aimed to evaluate the effect of dietary live yeast supplementation on ruminal pH pattern, fermentation characteristics and associated bacteria in beef cattle.Methods: This work comprised of in vitro and in vivo experiments. In vitro fermentation was conducted by incubating 0%, 0.05%, 0.075%, 0.1%, 0.125%, and 0.15% active dried yeast (Saccharomyces cerevisiae, ADY) with total mixed ration substrate to determine its dose effect. According to in vitro results, 0.1% ADY inclusion level was assigned in in vivo study for continuously monitoring ruminal fermentation characteristics and microbes. Six ruminally cannulated steers were randomly assigned to 2 treatments (Control and ADY supplementation) as two-period crossover design (30-day). Blood samples were harvested before-feeding and rumen fluid was sampled at 0, 3, 6, 9, and 12 h post-feeding on 30 d.Results: After 24 h in vitro fermentation, pH and gas production were increased at 0.1% ADY where ammonia nitrogen and microbial crude protein also displayed lowest and peak values, respectively. Acetate, butyrate and total volatile fatty acids concentrations heightened with increasing ADY doses and plateaued at high levels, while acetate to propionate ratio was decreased accordingly. In in vivo study, ruminal pH was increased with ADY supplementation that also elevated acetate and propionate. Conversely, ADY reduced lactate level by dampening Streptococcus bovis and inducing greater Selenomonas ruminantium and Megasphaera elsdenii populations involved in lactate utilization. The serum urea nitrogen decreased, whereas glucose, albumin and total protein concentrations were increased with ADY supplementation.Conclusion: The results demonstrated dietary ADY improved ruminal fermentation dosedependently. The ruminal lactate reduction through modification of lactate metabolic bacteria could be an important reason for rumen pH stabilization induced by ADY. ADY supplementation offered a complementary probiotics strategy in improving gluconeogenesis and nitrogen metabolism of beef cattle, potentially resulted from optimized rumen pH and fermentation.

Development and on-orbit operation of loop heat pipes on chinese circumlunar return and reentry spacecraft

Zhang Hongxing,Mi Min,Miao Jianyin,Wang Lu,Chen Yang,Ding Ting,Ning Xianwen,Huo Yuhua 대한기계학회 2017 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.31 No.6

This paper describes the development and result of ground experiment and analyzes the on-orbit operation of Loop heat pipes (LHP) for the Chinese circumlunar return and reentry spacecraft. A novel LHP was developed to satisfy the thermal control requirements of Inertial measurement units (IMU). The LHP consisted of an integrated evaporator subassembly, a cambered condenser, and an electric explosion valve. Ground experiments were conducted to investigate the startup characteristics, and heat transfer and heat insulation performance of the LHPs. During a flight mission, the LHPs work as a thermal switch and perform both heat transfer and insulation functions. Before returning to the earth’s atmosphere, the valves of the reentry capsule are opened to discharge working fluid and prevent heat transfer from the capsule wall to the devices. In the flight mission, the LHPs performed all the required functions, and the IMU temperatures were maintained within an allowable range.

Fe-curcumin Nanozyme-Mediated Immunosuppression and Anti-inflammation in Experimental Autoimmune Uveitis

Zhengxuan Jiang,Kun Liang,Xiang Gao,Fan Cao,Guangqi An,Siyu Gui,Weiwei Tang,Liping Du,Liming Tao,Xianwen Wang 한국생체재료학회 2023 생체재료학회지 Vol.27 No.00

Background EAU is an inflammatory disease usually characterized by autoinflammation and autoimmunity and is aggravated by excessive generation of ROS. Conventional hormone therapy often has more adverse effects. It is urgent to find a therapeutic drug with higher efficiency and fewer adverse effects. Methods We developed an Fe-curcumin nanozyme in which natural antioxidants coordinate with Fe3+ to form nanoparticles with excellent solubility for directing anti-inflammatory and ROS scavenging effects to treat EAU. Several experiments were used to detect the characteristics of nanozymes. EAU model rats were used to detect the abilities of decreasing autoinflammation and autoimmunity. PBMCs were used to detect the ability to inhibit cell proliferation. Results Free radical scavenging experiments showed that nanozymes decreased the level of free radicals at low concentrations. In vitro and in vivo experiments revealed that the group treated with Fe-curcumin nanozymes had lower inflammatory reactions and ROS levels than the control group, as reflected by the downregulated levels of several critical inflammatory cytokines, such as IFN-γ, IL-17, and TNF-α; decreased H2O2 release; inhibited proliferation of Th1 and Th17 cells; and alleviated pathological changes in the eye. Importantly, the Fe-curcumin nanozyme was detected in the retina using Prussian blue staining. Additionally, Fe-curcumin nanozyme is noncytotoxic when directing these biological activities. Conclusion This study has demonstrated the feasibility of using the Fe-curcumin nanozyme as a nanodrug to inhibit inflammatory reactions and scavenge ROS in the treatment of EAU, indicating that it may serve as a promising therapeutic agent in clinical treatment.