Effect of Time Interval on Speed Estimation using Single Loop Detector Measurements

Jianhua Guo,Wei Huang,Yun Wei,Lin Zhang 대한토목학회 2013 KSCE JOURNAL OF CIVIL ENGINEERING Vol.17 No.5

Considering the importance of estimating speed from single loop detector measurements for many Intelligent Transportation System (ITS) related applications, a variety of algorithms have been developed in the literature for specific time intervals. However,the performance of these algorithms over a spectrum of time intervals has not yet received appropriate attention in the transportation research community. In this study, a Kalman filter based algorithm is selected as a typical representative and investigated over a spectrum of 30 time intervals starting from 1-minute to 30-minute with one minute increment. Empirical results using real world data show that the selected algorithm has workable performances for most of the time intervals under investigation. Specifically, the performances of the selected approach improve for intervals from 1-minute to 5-minute, stay stable for intervals between 5-minute and 15-minute, and decrease slightly for longer time intervals greater than 15-minute. The results demonstrate the ability of the selected algorithm to be readily implemented in a variety of transportation applications with specific time interval needs. Future work is recommended to develop a framework of coupling speed estimating algorithms and real world transportation applications through investigating other single loop speed estimation approaches and ITS application related time interval needs.

Econometrical Investigation on Infrastructure Investment and Economic Development in China: A Case Study Using Vector Autoregression Approach

Jianhua Guo,Jianping Guo,Jingxin Xia 대한토목학회 2011 KSCE Journal of Civil Engineering Vol.15 No.3

Over the decades, numerous studies have been conducted on investigating the relationship between economic development and infrastructure investment with a wide range of results. Targeting developing countries, this study analyzed this relationship using Gross Domestic Product (GDP), railway mileage, and highway mileage from Year 1964 to Year 2004 in China within the general Vector Autoregression (VAR) framework. Non-stationarity test showed that the selected macroeconomic variables are non-stationary with integration order 1. In addition, cointegration and error correction analyses showed that the selected variables are cointegrated with positive contribution of railway investment to GDP and negative contribution of highway investment to GDP in the long run. The findings are discussed and argued as in agreement with the infrastructure development situation in China. Social and economic situations relating to the analysis are discussed, based on which future research is recommended on handling the data generating mechanism change and the social and economic diversity across different regions in China.

GROWTH AND MICROSTRUCTURES OF ULTRATHIN Bi 2 Te 3 NANOPLATES BY MODIFIED HOT WALL EPITAXY

JIANHUA GUO,HUIYONG DENG,YUCONG LIU,GUJIN HU,XIAONAN LI,GUOLIN YU,NING DAI 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2014 NANO Vol.9 No.6

Ultrathin Bi 2 Te 3 nanoplates have been grown on an oxidized silicon substrate by a modi¯ed hotwall epitaxy (HWE) method, in which a quartz plate with holes was employed. The micro-structures and optical properties of Bi 2 Te 3 nanoplates were investigated by X-ray di®raction(XRD), scanning electron microscopy (SEM), atomic force microscope (AFM) and micro-Ramanspectroscopy. The results show that ultrathin Bi 2 Te 3 nanoplates with the thickness of about sixquintuple layers (QLs) are obtained, which is di±cult for the traditional HWE technique. TheRaman vibration mode A11gfrom the nanoplates exhibits an obviously red shift with decreasingthickness. The thickness variation of one nanoplate was obtained by the Raman map derivedfrom the vibration frequency of A11gmode and is in good agreement with the AFM result, whichindicates that Raman map is an e®ective method to characterize the thickness di®erence ofultrathin Bi 2 Te 3 nanoplates.

Study on the electroporation technology in Agaricus bisporus Breeding

Jianhua Liao,Zesheng Wang,Meiyuan Chen,Zhenghui Lu,Zhongjie Guo,Hongrong Li 한국버섯학회 2004 한국버섯학회 국제학술대회 Vol.3 No.-

Surface Modification by Self-Assembled Coating with Amphiphilic Comb-Shaped Block Copolymers: A Solution to the Trade-Off Among Solubility,Adsorption and Coating Stability

Ruiwei Guo,Yifan Liu,Yao Zhang,Anjie Dong,Jianhua Zhang 한국고분자학회 2013 Macromolecular Research Vol.21 No.10

Surface coating with amphiphilic block copolymers containing a long hydrophobic anchor block in polar solvent often suffered from the damaging impact of micelles, often leading to a significant decrease in adsorption amount and packing density. In this study, a series of amphiphilic comb-shape block copolymers, poly[poly(ethylene glycol) methyl ether acrylate]-b-poly(styrene-co-N,N-dimethylacrylamide) (P(PEGMEA)-b-P(St-DMA)) were synthesized successfully by reversible addition-fragmentation chain transfer (RAFT) polymerization with fluorescencelabelled RAFT agent. The chain structure and chemical composition of copolymers were characterized by 1H NMR,FTIR and GPC. The surface self-assembled coating through physical adsorption of P(PEGMEA)-b-P(St-DMA) in ethanol on the surface of polyacrylonitrile (PAN) membrane was investigated by XPS, ATR-FTIR, SEM and water contact angle measurements. The antifouling properties of the modified membranes were evaluated using BSA as a model protein. It was found that the introduction of appropriate DMA (DMA/St in the range of about 0.1 to 0.2) into the hydrophobic segment can significantly increase the solubility of copolymers and alter their aggregation behaviors,alleviate the impact of micelles, increase adsorbed amount of copolymers, and thus can enhance the hydrophilicity and anti-fouling properties of membranes. Moreover, the stability analysis indicated that P(PEGMEA)-b-P(St-DMA) with appropriate DMA in the hydrophobic anchor block can form a relatively stable coating on the surface of PAN membrane. Consequently, the adjustment of the structure and composition of anchor segment may be a potential solution to the trade-off among solubility, adsorption amount and coating stability when amphiphilic block copolymers were used to surface modification by self-assembled coatings.

Facile template-free one-pot fabrication of TiO2@C microspheres with high visible-light photocatalytic degradation activity

Hongxu Guo,Zishan Zheng,Jianhua Chen,Wen Weng,Mingqiang Huang 한국공업화학회 2016 Journal of Industrial and Engineering Chemistry Vol.36 No.-

TiO2@C microspheres were fabricated through facile template-free one-pot hydrothermal reaction, inwhich ferrocene was first simultaneously used as carbon source and structure directing agent. Thecomposite obtained have been characterized by X-ray powder diffraction, field emission scanningelectron microscopy, diffuse reflectance spectroscopy, X-ray photoelectron spectroscopy, and nitrogenadsorption–desorption isotherms. The results show that the peripheries of the microspheres are stackedby several TiO2 particles. The band gap energy the as-prepared sample is estimated to be 2.26 eV. Allcarbon species in the composite are modified on the surface of the photocatalyst. The as-preparedTiO2@C microspheres exhibited higher visible-light photocatalytic activity for the degradation of organicpollutants (Congo red and 4-nitrophenol) than that of N-doped TiO2 catalyst. The OH radicals formed inthe process of photocatalytic degradation were also detected through fluorescence technique.

Improving organic field-effect transistors based on double active layers structure

Xinan Guo,Feifei Xing,Fei Hong,Jianhua Zhang,Bin Wei,Jun Wang 한국물리학회 2010 Current Applied Physics Vol.10 No.1

Organic field-effect transistors (OFETs) were fabricated based on double active layers structure. Different substrate temperatures and thermal treatment were adopted to prepare double active layers and optimize film morphology. The grain size of organic films can be effectively controlled by the change in substrate temperature in the process of deposition. An improved device performance was obtained compared with conventional single layer devices. This result is attributed to the introduction of double active layers. We believe that this kind of optimization will simultaneously improve charge injection and transportation of OFETs.

Adsorption behavior of Congo red from aqueous solution on La2O3-doped TiO2 nanotubes

Hongxu Guo,Jianhua Chen,Wen Weng,Zishan Zheng,Dongfang Wang 한국공업화학회 2014 Journal of Industrial and Engineering Chemistry Vol.20 No.5

Composite adsorbent, TiO2 nanotubes doped by La2O3, were prepared and characterized by IR, XRD, SEM, and XPS, their adsorption properties were investigated in the aqueous solution employing Congo red as the target pollutant. The adsorption experiments exhibited that adsorption equilibrium of Congo red over the adsorbent was rapidly achieved within 10 min, and the adsorption kinetics was in accord with the pseudo-second-order kinetics model. Moreover, intraparticle diffusion was not the determining step in the entire adsorption process, and the adsorption belonged to a chemical adsorption. Langmuir, Freundlich, Temkin and Dubinin–Radushkevich isothermal equations were utilized to fit the equilibrium adsorption data, in which the Temkin equation was verified to fit the adsorption behaviors most satisfactorily with the correlation coefficient of 0.998. The adsorption mechanism was also studied.

Initiation Mechanisms of Styrene with Methyl Ethyl Ketone Peroxide- Cobalt System

Ruiwei Guo,Yaqi Wang,Yongtao Qi,Auke G Talma,Jianhua Zhang 한국고분자학회 2018 Macromolecular Research Vol.26 No.8

Unsaturated polyester resins (UPR) cured with styrene has been widely used in the various industrial fields. Methyl ethyl ketone peroxides (MEKP)-cobalt(II) system is the most common initiator for the curing of UPR. However, its initiation mechanisms currently remain elusive. In this study, the monomeric MEKP (MEKP-1) was firstly separated out from the commercial MEKP products, and then the radical initiation mechanisms of MEKP-1 catalyzed by cobalt isooctoate in the presence and absence of styrene were comparatively investigated by a combination of nitroxide radical trapping technique and HPLC-ESI/MS (high performance liquid chromatography- electrospray ionization/mass spectrometry). The amount of trapped products originated from methyl radical, ethyl radical and hydroxyl radical was significantly larger than that of trapped products from other radicals. These results indicated that methyl, ethyl and hydroxyl radicals were the dominant intermediate radicals formed in the initiation process of MEKP-cobalt(II) system, which would serve as the primary source to initiate styrene polymerization.

1,4-Di(3-alkoxy-2-thienyl)-2,5-difluorophenylene: A Building Block Enabling High-Performance Polymer Semiconductors with Increased Open-Circuit Voltages

Chen, Jianhua,Yan, Zhenglong,Tang, Linjing,Uddin, Mohammad Afsar,Yu, Jianwei,Zhou, Xin,Yang, Kun,Tang, Yumin,Shin, Tae Joo,Woo, Han Young,Guo, Xugang American Chemical Society 2018 Macromolecules Vol.51 No.14

<P>A new building block, 1,4-di(3-alkoxy-2-thienyl)-2,5-difluorophenylene (DOTFP) with several desirable features such as high backbone planarity, suitably lying highest occupied molecular orbital (HOMO), and good solubility, was developed by inserting an electron-deficient difluorophenylene into the 3,3′-dialkoxy-2,2′-bithiophene (BTOR) unit. Three regioregular D-A<SUB>1</SUB>-D-A<SUB>2</SUB> type polymers based on DOTFP and benzothiadiazole (BT) derivatives were synthesized and characterized by comparing with a D-A type BTOR-based polymer. The content of highly electron-rich alkoxythiophene is reduced by half in the DOTFP-based polymers versus that of the BTOR-based polymer analogue, which results in a deeper HOMO level and benefits high open-circuit voltage (<I>V</I><SUB>oc</SUB>) in polymer solar cells (PSCs). Consequently, the DOTFP-ffBT-based solar cells exhibited a significantly improved power conversion efficiency (PCE) of 8.7% and an increased <I>V</I><SUB>oc</SUB> of 0.84 V compared to the BTOR-ffBT-based solar cells with a PCE of 2.6% and a <I>V</I><SUB>oc</SUB> of 0.49 V. Additionally, the DOTFP-based polymers showed improved charge transport properties and film morphology than the BTOR-based polymer BTOR-ffBT, resulting in simultaneous enhancement of the short-circuit current (<I>J</I><SUB>sc</SUB>) and fill factor (FF) in PSCs. These results demonstrate the great promise of the DOTFP building block for the construction of high-performance photovoltaic polymer semiconductors with increased <I>V</I><SUB>oc</SUB>s.</P> [FIG OMISSION]</BR>