AN INERTIAL MANIFOLD FOR A NON-SELF ADJOINT SYSTEM

( Xiuxiu Sun ) 호남수학회 2020 호남수학학술지 Vol.42 No.4

In this work, we prove an existence of an inertial manifold for a system of differential equations with a non-self adjoint leading part. The result follows from the existence and uniqueness of negatively bounded solutions. In fact, we show that a sharp spectral condition is sufficient for the proof.

Expanding Ring Search Energy Analysis and Optimization for Wireless Sensor Networks

Xiuxiu Wen,Huiqiang Wang,Guangsheng Feng,Hongwu Lv,Junyu Lin,Qiang Zhu 보안공학연구지원센터 2016 International Journal of Smart Home Vol.10 No.9

Expanding Ring Search (ERS) is an advanced flooding technique exploring for targets progressively. It is widely used to locate destinations or information in wireless sensor networks. In this paper, a fundamental problem concerning the best ERS strategy to minimize energy cost in wireless sensor networks is addressed. We propose a model for estimating the average energy cost of ERS strategies, and a model for comparing the energy cost of an ERS strategy with pure flooding. The second model is then used to prove that incremental ERS strategies are inefficient in large-scale wireless sensor networks. Furthermore, we propose an ERS strategy optimization algorithm SSetOpt, which can be applied to both dense wireless sensor networks and sparse ones. The simulation results show that the strategy obtained by SSetOpt can cost 5% less energy than prior works when the network is sparse, say, the average degree is less than 30..

Destination image and Revisit Intention of Zhangjiakou's Ski Tourism in the Post-Winter Olympics Era: Mediating Role of Perceived Value and Satisfaction

( Jianmin Shi ),( Lei Qiang ),( Xiuxiu Bu ),( Xing Yan ) 한국융합과학회 2022 한국융합과학회 국제학술대회자료집 Vol.2022 No.0

Introduction Since the opening of the first Winter Olympics in 1924, it has gone through 24 times, and its century-long development has always promoted the spread and promotion of the spirit and culture of the Olympic Movement. In the development of the Olympic Movement, sustainability has gradually become an indispensable theme. (Olympic Agenda 2020+5, 2020). In the current society, sustainable development has gradually become a behavioral standard and value system widely recognized by the international community (Sustainable Development, 2015). Especially in the Olympic venues, the concept of sustainable development also played an important guiding role. The main function of these venues is to serve the competition, and the utilization and sustainable development of the venues after the competition has become a matter of concern (Beijing 2022 Olympic and Paralympic Winter Games Sustainability Plan, 2019). As one of the co-hosts of the 2022 Beijing Winter Olympics, Zhangjiakou ice and snow tourism has developed rapidly. During the 2020-2021 snow season, Zhangjiakou City will receive 2.462 million tourists, a year-on-year increase of 83%. (Zhangjiakou News Network, 2022). It is not difficult to see from the growth of tourists that the Winter Olympics will have a positive impact on Zhangjiakou's tourism industry, indicating that Zhangjiakou's ice and snow tourism industry has begun to take shape and is gaining momentum. For example, in 2003, the number of tourists in Zhangjiakou Wanlong Ski Resort was less than 10,000. In the 2015 snow season (the year of the successful Olympic bid), the number of tourists soared to more than 200,000. In the 2020-2021 snow season, this number has reached 368,000 (China Business Network, 2022). With the end of the 2022 Winter Olympics, Zhangjiakou lacks a lot of exposure compared to the Winter Olympics, and it is unclear whether this momentum can continue. To promote sustainable tourism in Zhangjiakou, it is important to understand tourists’ decision-making processes because maintaining a substantial number of tourists is a necessary condition for sustainable tourism development (Jin et al., 2019). In the tourism sector, an important thing is to ensure that tourists revisit specific places in the future, which depends on the first visit experience and attractions (Osman & Sentosa , 2013). Oppermann (1998); Gyte and Phelps (1989); Gitelson and Crompton (1984) pointed out that revisiting tourists can effectively reduce the market cost of tourist destinations, increase economic benefits, maintain a stable source of tourists and bring positive tourist word-of-mouth effect. For tourist destinations, tourists' willingness to revisit is an important indicator of their business development.One of the factors influencing sport tourists' revisit is tourists' inference from destination image, perceived value which attracts sport tourists and it is necessary to develop it (Chen & Tsai, 2007; Quintal & Polczynski, 2010). Although tourism literature has paid attention to perceived value, however, tourism researchers and practitioners have not paid equal attention to the customer's service experience (Lee et al., 2007; Dong & Siu, 2013). In fact, the importance of visitor experience cannot be overemphasized, tourists who experience satisfactory traveling services and destination, they would have more intentions to visit the same destinations again(Kim & Brown,2012; San et al., 2019). Mazanec et al. (2007) showed that while the competitiveness of a tourism destination is considered as the ability of that destination to provide services, memorable experience and customers' satisfaction and consequently to increase their revisit and more earning for that destination, this concept is only a definition. Tourists' revisit depends on their satisfaction from destination (Guntoro & Hui, 2013). Research on the factors influencing tourists' revisit of sport tourism destinations can provide strategies to increase the attraction of sport tourists and to improve the economic level of the destinations. Given the importance of the above, this study explores the relationship between destination image, perceived value, satisfaction, and revisit intention of ski tourism destinations. Importantly, these variables have not been studied as a comprehensive model in Zhangjiakou as a tourist destination until now.Within this framework, the primary factors in sustainable development of a destination become clearer, offering guidance to researchers and destination marketers alike. Methods This study conducted a questionnaire survey on 500 ski tourists who went to Zhangjiakou after the Winter Olympics. The collected data were analyzed by descriptive statistics, exploratory factor analysis, confirmatory factor analysis, structural equation modeling, intermediary effect analysis. Result and Discussion

REMARKS ON THE EXISTENCE OF AN INERTIAL MANIFOLD

Kwak, Minkyu,Sun, Xiuxiu Korean Mathematical Society 2021 대한수학회지 Vol.58 No.5

An inertial manifold is often constructed as a graph of a function from low Fourier modes to high ones and one used to consider backward bounded (in time) solutions for that purpose. We here show that the proof of the uniqueness of such solutions is crucial in the existence theory of inertial manifolds. Avoiding contraction principle, we mainly apply the Arzela-Ascoli theorem and Laplace transform to prove their existence and uniqueness respectively. A non-self adjoint example is included, which is related to a differential system arising after Kwak transform for Navier-Stokes equations.

Effect of Oxygen Functionalities of Graphene Oxide on Polymerization and Thermal Properties of Reactive Benzoxazine Nanocomposites

Wenkai Zhang,Yanshan Zhan,Xiuxiu Gao,Runming Li,Weiwei Zhu,Hao Xu,Baoying Liu,Xiaomin Fang,Yuanqing Xu,Tao Ding 한국고분자학회 2018 Macromolecular Research Vol.26 No.1

Herein, we report the effect of oxygen functionalities of graphene oxide on thermal activated polymerization and thermal properties of reactive benzoxazine nanocomposites. The numbers of oxygen moieties of graphene oxide (GO) are controlled by hydrothermal reduction. The polymerization behavior of benzoxazine monomer (BA-a) is studied by Fourier transform infrared spectroscopy, differential scanning calorimetry and rheological analysis. It is hypothesized that the GO not only exhibits accelerated effect on the polymerization of the BA-a, but also the oxygen moieties such as carboxyl groups of GO interact with the benzoxazine polymers, leading to several orders of magnitude increase in the chemoviscosity and modulus of composite system. Thermal conductivity of poly(BA-a)/GO composite increases from an initial value of ∼0.27 W/mK to 0.47 W/mK as the loading increases from 1 wt% to 6 wt% (enhancement factor up to 176%). Moreover, the nanocomposites display enhanced initial decomposition temperature and char yields as the degree of GO reduction increases.

Changes in fl avor-relevant compounds during vine ripening of tomato fruit and their relationship with ethylene production

Libin Wang,Weiqi Luo,Xiuxiu Sun,Chunlu Qian 한국원예학회 2018 Horticulture, Environment, and Biotechnology Vol.59 No.6

Flavor quality is import for determining consumer perception and acceptance of tomato products. In this study, ‘Fendou’tomato fruit were harvested at six ripening stages and sampled to investigate the development of fl avor-relevant compoundsduring vine ripening. Results showed that upon the initiation of ripening there was an increase in respiration rate and concomitantethylene evolution that was associated with increased membrane permeability. In accordance with these physiologicalchanges, fl avor-relevant compounds demonstrated diff erent expression patterns as fruit ripened, which contributedto ‘red-ripe’ fl avor characteristics of red-ripe fruit. Based on correlation analysis between ethylene evolution and the fl avorrelevantcompounds during ‘Fendou’ tomato ripening and the other researchers’ reports, the activation of System 2-dependentautocatalytic ethylene production plays an important role in the development of most fl avor-relevant compounds duringtomato vine ripening. Overall, our results suggested that most fl avor-relevant compounds that accumulated the most duringtomato fruit ripening at red stage could be under ethylene regulation and were among the most important contributors tothe ‘red-ripe’ fl avor. Due to the development of these compounds, the fl avor quality at late ripening stages is diff erent fromthat of fruit at early ripening stages.

The Rehabilitation-Related Effects on the Fear, Pain, and Disability of Patients With Lumbar Fusion Surgery: A Systematic Review and Meta-Analysis

Haiyan Cheng,Jing Liu,Lin Shi,Xiuxiu Hei 대한척추신경외과학회 2023 Neurospine Vol.20 No.1

Objective: The lumbar fusion is an important surgery for the orthopedic diseases. The rehabilitation might improve the outcome of patients with lumbar fusion surgery. The rehabilitation-related effects can be revealed by a systemic review and meta-analysis of randomized clinical trials (RCTs). The purpose of this study is to clarify the rehabilitation effects in the patients with lumbar fusion surgery. Methods: We performed a systematic search and a meta-analysis for the RCT of rehabilitation treatment on the patients with lumbar fusion surgery. The comparison between rehabilitation treatment (including psychological rehabilitation, exercise, and multimodal rehabilitation) and typical treatment was performed to find if the rehabilitation treatment can improve the outcome after the lumbar fusion surgery. Fifteen studies of lumbar fusion patients under rehabilitation treatment and typical treatment were enrolled in a variety of rehabilitation modalities. The focused outcome was the rehabilitation-related effects on the fear, disability, and pain of patients after the lumbar fusion surgery. Results: Five hundred twenty-eight rehabilitation subjects and 498 controls were enrolled. The psychological-related rehabilitation showed a significant decrease in pain-related fear when compared to usual treatment. The multimodal rehabilitation can improve the disability outcome to a greater extent when compared to usual treatment. The multimodal rehabilitation seemed to have a more significantly positive effect to decrease disability after lumbar fusion surgery. In addition, the exercise and multimodal rehabilitation can relieve the pain after lumbar fusion surgery. The exercise rehabilitation seemed to have a more significantly positive effect to relieve pain after lumbar fusion surgery. Conclusion: The rehabilitation might relieve the pain-related fear, disability, and pain after lumbar fusion surgery.

Functional roles and mechanisms of ginsenosides from Panax ginseng in atherosclerosis

Qianqian Xue,Ningning He,Zhibin Wang,Xiuxiu Fu,Lynn Htet Htet Aung,Yan Liu,Min Li,Jae Youl Cho,Yanyan Yang,Tao Yu 고려인삼학회 2021 Journal of Ginseng Research Vol.45 No.1

Atherosclerosis (AS) is a leading cause of cardiovascular diseases (CVDs) and it results in a high rate of death worldwide, with an increased prevalence with age despite advances in lifestyle management and drug therapy. Atherosclerosis is a chronic progressive inflammatory process, and it mainly presents with lipid accumulation, foam cell proliferation, inflammatory response, atherosclerotic plaque formation and rupture, thrombosis, and vascular calcification. Therefore, there is a great need for reliable therapeutic drugs or remedies to cure or alleviate atherosclerosis and reduce the societal burden. Ginsenosides are natural steroid glycosides and triterpene saponins obtained mainly from the plant ginseng. Several recent studies have reported that ginsenosides have a variety of pharmacological activities against several diseases including inflammation, cancer and cardiovascular diseases. This review focuses on describing the different pharmacological functions and underlying mechanisms of various active ginsenosides (Rb1,-Rd, -F, -Rg1, -Rg2, and -Rg3, and compound K) for atherosclerosis, which could provide useful insights for developing novel and effective anti-cardiovascular drugs.

Green catalyst derived from zero‑valent iron onto porous biochar for removal of Rhodamine B from aqueous solution in a Fenton‑like process

Chongqing Wang,Pau Loke Show,Xiuxiu Zhang,Yijun Cao,Yasser Vasseghian 한국탄소학회 2023 Carbon Letters Vol.33 No.7

Organic wastewater causes serious environmental pollution, and catalytic oxidation is promising technique for wastewater treatment. Developing green and effective catalysts is currently challenging. In this work, green synthesis of nano zerovalent iron loaded onto porous biochar derived from popcorn is conducted, and catalytic oxidation of Rhodamine B (RhB) is evaluated in the presence of H2O2. Effect of process factors is examined on catalytic performance for RhB removal. The mechanism of RhB removal is discussed by characterizations (Fourier transform infrared spectra and Raman) and UV–vis spectra. RhB removal is improved with high catalyst dosage, low initial RhB concentration, and high reaction temperature, while it is slightly influenced by carbonization temperature of biochar, H2O2 dosage and pH value. Under conditions of BC-250 1.0 g/L, H2O2 0.01 mol/L, pH 6.1, and temperature 30 °C, the removal rate of RhB is 92.27% at 50 min. Pseudo first-order kinetics is used to fitting experimental data, and the activation energy for RhB removal in BC-250/H2O2 system is 39 kJ/mol. RhB removal in BC-250/H2O2 system can be attributed to adsorption effect and catalytic oxidation with the dominant role of hydroxyl radical. This work gives insights into catalytic oxidation of organic wastewater using green catalyst.

Protective effect and mechanism of ginsenoside Rg2 on atherosclerosis

Qianqian Xue,Tao Yu,Zhibin Wang,Xiuxiu Fu,Xiaoxin Li,Lu Zou,Min Li,Jae Youl Cho,Yanyan Yang The Korean Society of Ginseng 2023 Journal of Ginseng Research Vol.47 No.2

Background: Ginsenoside Rg2 (Rg2) has a variety of pharmacological activities and provides benefits during inflammation, cancer, and other diseases. However, there are no reports about the relationship between Rg2 and atherosclerosis. Methods: We used 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) to detect the cell viability of Rg2 in vascular smooth muscle cells (VSMCs) and human umbilical vein endothelial cells (HUVECs). The expression of inflammatory factors in HUVECs and the expression of phenotypic transformation-related marker in VSMCs were detected at mRNA levels. Western blot method was used to detect the expression of inflammation pathways and the expression of phenotypic transformation at the protein levels. The rat carotid balloon injury model was performed to explore the effect of Rg2 on inflammation and phenotypic transformation in vivo. Results: Rg2 decreased the expression of inflammatory factors induced by lipopolysaccharide in HUVECs-without affecting cell viability. These events depend on the blocking regulation of NF-κB and p-ERK signaling pathway. In VSMCs, Rg2 can inhibit the proliferation, migration, and phenotypic transformation of VSMCs induced by platelet derived growth factor-BB (PDGF-BB)-which may contribute to its anti-atherosclerotic role. In rats with carotid balloon injury, Rg2 can reduce intimal proliferation after injury, regulate the inflammatory pathway to reduce inflammatory response, and also suppress the phenotypic transformation of VSMCs. Conclusion: These results suggest that Rg2 can exert its anti-atherosclerotic effect at the cellular level and animal level, which provides a more sufficient basis for ginseng as a functional dietary regulator.