Theoretical and Experimental Studies on the Kinetics of Cation Redistribution Processes in Complex Oxides

Shi, Jianmin,Becker, Klaus-Dieter The Korean Ceramic Society 2010 한국세라믹학회지 Vol.47 No.1

The kinetics of cation reequilibration have been studied theoretically and experimentally in complex oxides after an external perturbation of equilibrium by temperature jumps. A general kinetic model for cation redistribution amongst non-equivalent sites in complex oxides is derived based on a local homogeneous point defect mechanism involving cation vacancies. Temperature-jump optical relaxation spectroscopy has been established to investigate cation kinetic processes in spinels and olivines. The kinetic model satisfactorily describes the experimental absorbance relaxation kinetics in cobalt containing olivines and in nickel containing spinels. It is found that the kinetics of cation redistribution in complex oxides shows a strong temperature- and composition-dependence. Activation energies for cation redistribution in Co-Mg olivines are found to range between 200 and 220 kJ/mol whereas an energy barrier of about 230 kJ/mol is observed in the case of nickel gallate spinel.

Theoretical and Experimental Studies on the Kinetics of Cation Redistribution Processes in Complex Oxides

Jianmin Shi,Klaus-Dieter Becker 한국세라믹학회 2010 한국세라믹학회지 Vol.47 No.1

The kinetics of cation reequilibration have been studied theoretically and experimentally in complex oxides after an external perturbation of equilibrium by temperature jumps. A general kinetic model for cation redistribution amongst non-equivalent sites in complex oxides is derived based on a local homogeneous point defect mechanism involving cation vacancies. Temperature-jump optical relaxation spectroscopy has been established to investigate cation kinetic processes in spinels and olivines. The kinetic model satisfactorily describes the experimental absorbance relaxation kinetics in cobalt containing olivines and in nickel containing spinels. It is found that the kinetics of cation redistribution in complex oxides shows a strong temperature- and compositiondependence. Activation energies for cation redistribution in Co-Mg olivines are found to range between 200 and 220 kJ/mol whereas an energy barrier of about 230 kJ/mol is observed in the case of nickel gallate spinel.

Relationships between Motivation, Goal Orientation, Satisfaction, and Adherence in Skiers at Beijing Ski Resorts

Jianmin Shi,Xiaodai Jia,Yan Xing,Xiuxiu Bu,Qiang Lei,Qunqun Sun 아시아스포츠융합과학회 2023 Asia Pacific Journal of Applied Sport Sciences Vol.4 No.1

PURPOSE Based on theoretical evidence and previous literature, this study proposes research hypotheses and establishes a structural equation model (SEM) that includes variables such as motivation, goal orientation, satisfaction, and adherence. METHOD Study participants included skiers at the ski resorts located around Beijing. In total, 700 questionnaires were distributed, and 44 invalid questionnaires were removed for being incomplete or incorrect; 656 questionnaires were retained and analyzed using SPSS v. 26 and Amos v. 23. Descriptive statistics, exploratory factor analysis, confirmatory factor analysis, and structural equation modeling methods were used in the analyses. RESULT This study explored the relationship between motivation, goal orientation, satisfaction, and adherence in skier participants through a quantitative analysis. Through the establishment and verification of the structural equation mode, the following conclusions were drawn: First, motivation directly affects goal orientation. Second, motivation directly affects satisfaction. Third, motivation directly affects adherence. Fourth, goal orientation directly affects satisfaction. Fifth, goal orientation directly affects adherence. Sixth, satisfaction directly affects adherence. CONCLUSION To improve skiing adherence, Beijing ski resort operators should understand the motivation for skiing, formulate supporting policies and services, and enhance the goal orientation and satisfaction of skiers. This study provides some practical implications for ski resort operators that may increase the profit of ski resorts contribute to the sustainable development of Beijing skiing.

Oxidation kinetics of nitrogen doped TiO_{2−<i>δ</i>} thin films

Shi, Jianmin,Lee, Doh-Kwon,Yoo, Han-Ill,Janek, Jü,rgen,Becker, Klaus-Dieter The Royal Society of Chemistry 2012 Physical chemistry chemical physics Vol.14 No.37

<P>The oxidation kinetics of nitrogen doped, oxygen deficient titanium dioxide thin films has been studied in atmospheres of pure oxygen or nitrogen at 500 °C, 550 °C, and 600 °C, respectively, by means of <I>in situ</I> optical spectroscopy. The thin films show high electronic absorbance in the visible and NIR region, accompanied by a red shift of the absorption edge of about 0.4 eV, <I>e.g.</I>, from about 2.9 to 2.5 eV at 600 °C. The time dependent decrease of absorbance due to oxidation is found to follow a parabolic rate law. An activation energy of about 1.96 eV can be obtained from the temperature dependence of the parabolic oxidation rate constant. In the framework of a microscopic oxidation model, this energy barrier is attributed to the diffusion of titanium interstitials in the re-oxidized part of the thin films as a rate-determining process. In addition, an attempt is made to evaluate the kinetics of nitrogen release from the time dependent blue shift of the absorption edge during re-oxidation.</P> <P>Graphic Abstract</P><P>Oxidation kinetics of N-doped TiO<SUB>2−<I>δ</I></SUB> thin film has been studied using optical spectroscopy under <I>in situ</I> conditions, revealing the dominance of Ti<SUP>4+</SUP>-interstitial diffusion. <IMG SRC='http://pubs.rsc.org/services/images/RSCpubs.ePlatform.Service.FreeContent.ImageService.svc/ImageService/image/GA?id=c2cp42559a'> </P>

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

Uncovering Taxi Mobility Patterns Associated with the Public Transportation Shutdown Using Multisource Data in Washington, D.C.

Jianmin Jia,Hui Zhang,Baiying Shi 대한토목학회 2022 KSCE JOURNAL OF CIVIL ENGINEERING Vol.26 No.12

The relationship between taxi travel patterns and public transportation disruption has not been extensively explored. In this study, we investigated the impact of public transportation disruption on the taxi mobility patterns during the metro shutdown in Washington, D.C.. Multiple data source, involving taxi trips, traffic analysis zone, and point of interest (POI) information, was collected to compare the taxi travel patterns before, during, and after the metro shutdown. The number, distance, and duration of taxi trips were found to be significantly higher during the metro shutdown; specifically, the number of taxi trips was found to be 19.8% larger. Furthermore, a POI auxiliary analysis was performed to investigate the variation in community structure during the disruption of public transport using the modularity maximization approach. The results of this study will be useful for the development of taxi scheduling strategies and traffic management.

Effects of three drying methods on polyphenol composition and antioxidant activities of Litchi chinensis Sonn.

Si Tan,Jianmin Tang,Wenjing Shi,Zhuwei Wang,Yuanyuan Xiang,Tingwei Deng,Xiaoxu Gao,Wenfeng Li,Shengyou Shi 한국식품과학회 2020 Food Science and Biotechnology Vol.29 No.3

The aim of this study was to investigate the effects of three different drying methods, freeze drying (FD), vacuum drying (VD) and oven drying (OD) on phenolic contents and antioxidant activities of litchi fruits. 20 polyphenols were exactly identified in the litchi fruits by UPLC-QqQ/MS. Significant losses were observed in the contents of total polyphenols and antioxidant activities in the dried litchi when compared with the fresh litchi. Principle component analysis indicated that there was significant difference of phenolic component between the use of thermal drying (VD and OD) and FD. Our results suggest that FD is the optimum drying method for litchi fruits considering the content of total polyphenols and antioxidant activities.

The effect of cooling conditions on convective heat transfer and flow in a steam-cooled ribbed duct

Linqi Shui,Jianmin Gao,Xiaojun Shi,Jiazeng Liu,Liang Xu 대한기계학회 2014 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.28 No.1

This work presents a numerical and experimental investigation on the heat transfer and turbulent flow of cooling steam in a rectangularduct with 90° ribs and studies the effect of cooling conditions on the heat transfer augmentation of steam. In the calculation, the variationrange of Reynolds is from 10,000 to 190,000, the inlet temperature varies from 300°C to 500°C and the outlet pressure is from 0.5MPa to6MPa. The aforementioned wide ranges of flow parameters cover the actual operating condition of coolant used in the gas turbine blades. The computations are carried with four turbulence models (the standard k-ε, the renormalized group (RNG) k-ε, the Launder-Reece-Rodi(LRR) and the Speziale-Sarkar-Gatski (SSG) turbulence models). The comparison of numerical and experimental results reveals that theSSG turbulence model is suitable for steam flow in the ribbed duct. Therefore, adopting the conjugate calculation technique, further studyon the steam heat transfer and flow characteristics is performed with SSG turbulence model. The results show that the variation of coolingcondition strongly impacts the forced convection heat transfer of steam in the ribbed duct. The cooling supply condition of a relativelow temperature and medium pressure could bring a considerable advantage on steam thermal enhancement. In addition, comparing theheat transfer level between steam flow and air flow, the performance advantage of using steam is also influenced by the cooling supplycondition. Changing Reynolds number has little effect on the performance superiority of steam cooling. Increasing pressure wouldstrengthen the advantage, but increasing temperature gives an opposite result.

The Relationship of Basketball Participation Motivation, Involvement, Satisfaction, and Adherence among Middle School Students in China

Peng Qiu,Jianmin Shi,Wang Zuo,Yan Xing 아시아스포츠융합과학회 2023 Asia Pacific Journal of Applied Sport Sciences Vol.4 No.2

PURPOSE This study aimed to examine the relationship among participation motivation (PM), involvement (IN), satisfaction (SA), and adherence (AD) in middle school basketball participants in China. METHOD Participants were recruited from 10 middle schools in Changchun, Tonghua, Baicheng, Yanbian, and Siping in Jilin Province, China. A total of 800 questionnaires were distributed, and around 793 questionnaires were used for the final analysis. Data were analyzed using SPSS 26 and AMOS 23. RESULT This study determined the PM, IN, SA, and AD of middle school basketball participants through quantitative analysis. Through the establishment and verification of the structural equation model, the following findings were revealed: first, PM directly affects IN. Second, PM directly affects the development of AD. Third, PM directly affects SA. Fourth, IN does not affect SA. IN directly affects the development of AD. Sixth, SA directly affects the development of AD. CONCLUSION To improve the AD of middle school students to participate in basketball, physical education managers and teachers in Jilin Province should first master students' PM and adopt strategies to strengthen it. They must understand students' needs for basketball participation through their IN while improving their SA. This study provides a theoretical reference for Chinese middle school basketball-related researchers. It may provide corresponding methods and strategies for increasing middle school students' basketball AD, thereby further aiding the steady development of the sport in Chinese middle schools.

Effect of plant secondary metabolites on common cutworm, Spodoptera litura (Lepidoptera: Noctuidae)

Qi Su,Zhixiong ZHOU,Jianmin ZHANG,Caihua SHI,Guohui ZHANG,Zhenyu JIN,Wenkai WANG,Chuanren LI 한국곤충학회 2018 Entomological Research Vol.48 No.1

The effect of various flavonoids, lectins and phenyl β‐D‐glucoside on larval survival, weights and the activities of digestive (total serine protease and trypsin) and detoxifying (esterase and glutathione‐S‐transferase) enzymes of Spodoptera litura larvae at 7 days after treatment was studied through diet incorporation assay. Flavonoids (rutin, chlorogenic acid, quinic acid, caffeic acid, naringenin, quercitin, kaempferol, myricetin, catechin, and ferulic acid) were incorporated in artificial diet at 100, 500 and 1000 ppm, lectins: groundnut leaf lectin (GLL), concavalin A (ConA) and phenyl β‐D‐glucoside at 1, 2 and 5 μg/mL. Flavonoids such as rutin, quercitin and kaempferol at 1000 ppm were more toxic to S. litura larvae than quinic acid, caffeic acid, naringenin, myricetin, catechin, and ferulic acid. Larval growth and development were significantly reduced in S. litura larvae fed on a diet with GLL and ConA at 5 μg/mL compared to the larvae fed at 2 and 1 μg/mL concentrations. The larvae fed on flavonoid‐treated diets showed significant reduction in serine protease, trypsin and esterase activities. The flavonoids such as rutin, chlorogenic acid, quinic acid, naringenin, quercitin, kaempferol and myricetin, and lectins, GLL and ConA can be utilized in insect control programs.