Catalytic performance of amino acid/phosphotungstic acid as bi-functional heterogeneous catalyst for biodiesel production

Qingyu Zhang,Xiaoling Duan,Siyi Tang,Cunwen Wang,Weiguo Wang,Weiliang Feng,Tielin Wang 대한환경공학회 2023 Environmental Engineering Research Vol.28 No.1

In this study, a series of acid-base bi-functional catalysts were prepared by mixing different amounts of basic amino acids (AAs) and phosphotungstic acid (PTA), which exhibited the excellent performance in catalyzing conversion of oleic acid (OA) for the biodiesel production. The physicochemical properties of the catalysts were characterized and analyzed using modern testing techniques and characterization methods such as XRD, FT-IR, XPS, SEM, TEM, and Hammett titration. The various influence parameters were optimized using the central composite design based the response surface methodology, where the maximum biodiesel yield of 97.0% was achieved at the MeOH/OA molar ratio of 5.9, the catalyst loading of 8%, reaction time of 6 h, and reaction temperature of 65℃. Furthermore, the stability and reusability of the prepared catalyst were also demonstrated. At last, the possible catalytic mechanism of the prepared catalyst was comprehensively described.

세계화된 관점에서 본 미학과 예술의 발달 : 커티스 L. 카터(Curtis L. Carter)와의 인터뷰

Qingyu Han 한국융합인문학회 2019 한국융합인문학 Vol.7 No.4

Exploring the Characteristics of High-Speed Rail and Air Transportation Networks in China: A Weighted Network Approach

Qingyu Qi,Oh Kyoung Kwon 인하대학교 정석물류통상연구원 2021 JOURNAL OF INTERNATIONAL LOGISTICS AND TRADE Vol.19 No.2

This study explores the characteristics of high-speed rail (HSR) and air transportation networks in China based on the weighted complex network approach. Previous related studies have largely implemented unweighted (binary) network analysis, or have constructed a weighted network, limited by unweighted centrality measures. This study applies weighted centrality measures (mean association [MA], triangle betweenness centrality [TBC], and weighted harmonic centrality [WHC]) to represent traffic dynamics in HSR and air transportation weighted networks, where nodes represent cities and links represent passenger traffic. The spatial distribution of centrality results is visualized by using ArcGIS 10.2. Moreover, we analyze the network robustness of HSR, air transportation, and multimodal networks by measuring weighted efficiency (WE) subjected to the highest weighted centrality node attacks. In the HSR network, centrality results show that cities with a higher MA are concentrated in the Yangtze River Delta and the Pearl River Delta; cities with a higher TBC are mostly provincial capitals or regional centers; and cities with a higher WHC are grouped in eastern and central regions. Furthermore, spatial differentiation of centrality results is found between HSR and air transportation networks. There is a little bit of difference in eastern cities; cities in the central region have complementary roles in HSR and air transportation networks, but air transport is still dominant in western cities. The robustness analysis results show that the multimodal network, which includes both airports and high-speed rail stations, has the best connectivity and shows robustness.

Effect of preparation of organic ferroelectric P(VDF-TrFE) nanostructure on the improvement of tennis performance

Qingyu Wang Techno-Press 2023 Advances in nano research Vol.14 No.4

Organic ferroelectric material found vast application in a verity of engineering and health technology fields. In the present study, we investigated the application of the deformable organic ferroelectric in motion measurement and improving performance in tennis players. Flexible ferroelectric material P(VDF-TrFE) could be used in wearable motion sensors in tennis player transferring velocity and acceleration data to collecting devises for analyzing the best pose and movements in tennis players to achieve best performances in terms of hitting ball and movement across the tennis court. In doing so, ferroelectric-based wearable sensors are used in four different locations on the player body to analyze the movement and also a sensor on the tennis ball to record the velocity and acceleration. In addition, poses of tennis players were analyzed to find out the best pose to achieve best acceleration and movement. The results indicated that organic ferroelectric-based sensors could be used effectively in sensing motion of tennis player which could be utilized in the optimization of posing and ball hitting in the real games.

Loess record of the evolution history of severe sandstorms in the Tengger Desert during the Last Interglacial Period (MIS5)

Qingyu Guan,Baotian Pan,Na Li,Qiong Li,Jundi Zhang,Shujian Xu,Hongshan Gao,Jia Liu 한국지질과학협의회 2010 Geosciences Journal Vol.14 No.2

The Shagou loess section recorded the evolution information of severe sandstorms in the Tengger Desert during the Last Interglacial (MIS 5). By analyzing the grain size data of the loess samples using the grain size class-standard deviation, we selected the grain size component between 209 and 550 µm to reconstruct the evolution history of the severe sandstorms in the Tengger Desert during the Last Interglacial. The results indicate that there were at least 12 periods of frequently occurring severe sandstorms in that location over this time period. There were two periods in each of S1SS1 and S1SS2, four periods in S1LL1, three periods in S1LL2 and one in S1LL4. The occurrence frequency and intensity of the severe sandstorms presented a characteristic increase from the early to the late period of the Last Interglacial. Combined with the calcium carbonate results, this evidence suggests that climatic change is closely related to sandstorms. A warm and wet climate could restrict the occurrence of severe sandstorms; conversely, a cold and dry climate easily induces severe sandstorms. Meanwhile, with a warm and dry climate background, the relationship between climatic change and the occurrence of sandstorms is quite complex: severe sandstorms are also able to occur in such a climate. A cold and dry climate, however, does not mean a certainty of severe sandstorms.

Pretest analysis of a prestressed concrete containment 1:3.2 scale model under thermal-pressure coupling conditions

Qingyu Yang,Jiachuan Yan,Feng Fan Korean Nuclear Society 2023 Nuclear Engineering and Technology Vol.55 No.6

In nuclear power plant (NPP) accidents, the containment is subject to high temperatures and high internal pressures, which may further trigger serious chain accidents such as core meltdown and hydrogen explosion, resulting in a significantly higher accident level. Therefore, studying the mechanical performance of a containment under high temperature and high internal pressure is relevant to the safety of NPPs. Based on similarity principles, the 1:3.2 scale model of a prestressed concrete containment vessel (PCCV) of a NPP was designed. The loading method, which considers the thermal-pressure coupling conditions, was used. The mechanical response of the PCCV was investigated with a simultaneous increase in internal pressure and temperature, and the failure mechanism of the PCCV under thermal-pressure coupling conditions was revealed.

Ambient noise surface wave tomography of Quaternary structures derived from a high-density array in the central Hebei Depression, North China

Qingyu Wu,Qiushneg Li,Xiangyun Hu,Zhanwu Lu,Wenhui Li,Xiaoran Wang 한국지질과학협의회 2023 Geosciences Journal Vol.27 No.2

Internal structure imaging of the Earth, along with determining basin structure, can aid in evaluating potential seismic hazards. However, the high operating cost limits the current geophysical exploration methods; moreover, it is difficult to apply these techniques over a large area, which limits our understanding of the Quaternary structure and the development of earthquake prevention science. A combination of dense array observation technology and ambient noise surface wave tomography is being rapidly developed as a high-resolution urban detection method. Here, we report the ambient noise imaging results of a high-density array experiment. In the ambient noise surface wave tomography method (e.g., surface wave tomography; Eikonal tomography), the signal is assumed to be a single mode. However, several multimode signals were detected in this dataset. With the use of traditional methods to measure the dispersion, mode confusion occurs and the extracted dispersion curve jumps. To solve this problem, by combining the advantages of phase-matched filtering and dispersion compensation, we realized the automatic pickup of fundamental group velocity using reference phase velocity. From this, a Rayleigh wave group velocity map was obtained. The regional average phase velocity information was included in the inversion steps to reduce the uncertainty in the inversion of shear wave velocity. Finally, an S-wave velocity structure model was obtained within a depth of 500 m. The velocity structure was roughly layered and grew with depth. In the depth range of 240–320 m, obvious decreases in the S-wave velocity were observed. Compared with geothermal drilling data, this was speculated to be the reflection of a water-rich (confined water) sand layer. This study provides a technical approach for and a processing example of a high-density array, and its velocity model can be used as a reference for urban subsurface structure, underground space utilization, and earthquake disaster prevention and control.

A Novel Impedance Measurement Method for Three-Phase Power Electronic Systems

Qingyu Dou,Zeng Liu,Jinjun Liu,Weihan Bao 전력전자학회 2015 ICPE(ISPE)논문집 Vol.2015 No.6

Power electronic systems could be unstable due to the interaction between converters. Impedance-based stability analysis is an effective approach to predict stability and to provide design criteria. Therefore significant are impedance measurement techniques, which have been well established for DC systems, but need to be improved for AC systems nevertheless. This paper proposes a novel AC impedance measurement method which injects bipolar pulse at current zero-crossing point. Compared with existing methods, it enhances accuracy and reduces distortion. Simulation and experimental results demonstrate the effectiveness of the novel method.

Diurnal and Nocturnal Behaviour of Airborne Cryptomeria japonica Pollen Grains and the Allergenic Species in Urban Atmosphere of Saitama, Japan

Qingyue Wang,Shinichi Nakamura,Senlin Lu,Daisuke Nakajima,Miho suzuki,Kazuhiko Sekiguchi,Makoto Miwa 한국대기환경학회 2013 Asian Journal of Atmospheric Environment (AJAE) Vol.7 No.2

Japanese cedar (Cryptomeria japonica) pollinosis is the most popular pollinosis in Japan. It has been reported that Cryptomeria japonica pollen allergenic species are suspended as fine particles in the urban atmosphere. These allergenic fine particles are responsible for inducing asthma by breaking into the lower respiratory tract. It has also been found that pollinosis symptoms on the sufferers appear mainly at night-time by the results from epidemiological studies. However, the exact reason for these phenomena is not yet clarified. In this study, the diurnal and nocturnal behaviours of Cryptomeria japonica pollen grains and their allergenic species in the urban area of Saitama city of Kanto Plain were investigated. Airborne pollen grains and allergenic Cry j 1 concentrations in total suspended particulate matter (TSP)were investigated at two sampling sites, a heavy traffic road (roadside site) and at the balcony of the 10th floor of the Building of Research and Project of Saitama University (general urban site). The latter sampling site where located about 300 m away from the roadside site was used as a general urban site unaffected by automobile traffic. The airborne pollen counts were measured with a real-time pollen monitor. Cry j 1 particles were collected with two high volume air samplers, and these concentrations were measured by surface plasmon resonance method with a Biacore J system. The diurnal variation of the airborne pollen counts was similar to the trends of temperature and wind speed during the day-time;whereas its tendency with wind speed trend was not observed during the night-time. Airborne pollen counts were lower with northern wind than with southern wind because the pollen comes from the mountainous areas, and the mountains in the south are closer, about half the distance to the northern mountains. It is suggested that the peaks of airborne pollen counts during night-time in the sampling site occurred by transport of pollen grains released during day-time in the mountainous forest areas, located c.a. 100 km away from the sampling site. On the roadside site the allergenic Cry j 1 concentrations were higher than at the general urban site, nevertheless pollen grains counts were lower. These results suggested that worsening of pollinosis symptoms during nighttime in urban area was caused by transport of pollen grains during day-time in the mountainous forest areas. Moreover, pollen allergenic species become different morphology from pollen grain at roadside site, and the subsequent pollen grains re-suspension by automobile traffic.

Size-segregated Allergenic Particles Released from Airborne Cryptomeria japonica Pollen Grains during the Yellow Sand Events within the Pollen Scattering Seasons

Qingyue Wang,Xiumin Gong,Miho Suzuki,Senlin Lu,Kazuhiko Sekiguchi,Daisuke Nakajima,Makoto Miwa 한국대기환경학회 2013 Asian Journal of Atmospheric Environment (AJAE) Vol.7 No.4

Cryptomeria japonica pollen is the most common pollen,which are scattering during each spring season in Japan. Japanese cedar (Cryptomeria japonica) pollinosis is one of seasonal allergic rhinitis that mainly occurs in Japan. In addition, long range transportation of Yellow Sand from the East Asian continent was also found during the pollen scattering seasons in Japan. Therefore, the interaction or impact between pollen and Yellow Sand should be concerned. In this study, our objective was to investigate the airborne behaviour of Cryptomeria japonica pollen grains and its size-segregated allergenic (Cry j 1)particles as the airborne tracer of Cryptomeria japonica pollen during the Yellow Sand events. Airborne Cryptomeria japonica pollen grains and its size-segregated allergenic particles were collected at roadside of urban residential zones of Saitama city during the pollination periods from February to March in two year investigation of 2009 and 2010. The overlap of Yellow Sand events and dispersal peak of pollen grains was observed. According to the Meteorological data,we found that the peaks of airborne pollen grains appeared under higher wind speed and temperature than the previous day. It was thought that Yellow Sand events and airborne pollen counts were related to wind speed. From the investigation of the airborne behavior of the size-segregated allergen particles by determining Cry j 1 with Surface Plasmon Resonance (SPR), the higher concentrations of the allergenic Cry j 1 were detected in particle size equal to or less than 1.1 μm(PM1.1) than other particle sizes during Yellow Sand events, especially in the rainy day. We conclude that rainwater trapping Yellow Sand is one of the important factors that affect the release of allergenic pollen species of Cry j 1. Therefore, it is very important to clarify the relationships between Cryptomeria japonica pollen allergenic species and chemical contents of the Yellow Sand particles in further studies.