Localized reliability analysis on a large-span rigid frame bridge based on monitored strains from the long-term SHM system

Liu, Zejia,Li, Yinghua,Tang, Liqun,Liu, Yiping,Jiang, Zhenyu,Fang, Daining Techno-Press 2014 Smart Structures and Systems, An International Jou Vol.14 No.2

With more and more built long-term structural health monitoring (SHM) systems, it has been considered to apply monitored data to learn the reliability of bridges. In this paper, based on a long-term SHM system, especially in which the sensors were embedded from the beginning of the construction of the bridge, a method to calculate the localized reliability around an embedded sensor is recommended and implemented. In the reliability analysis, the probability distribution of loading can be the statistics of stress transferred from the monitored strain which covered the effects of both the live and dead loads directly, and it means that the mean value and deviation of loads are fully derived from the monitored data. The probability distribution of resistance may be the statistics of strength of the material of the bridge accordingly. With five years' monitored strains, the localized reliabilities around the monitoring sensors of a bridge were computed by the method. Further, the monitored stresses are classified into two time segments in one year period to count the loading probability distribution according to the local climate conditions, which helps us to learn the reliability in different time segments and their evolvement trends. The results show that reliabilities and their evolvement trends in different parts of the bridge are different though they are all reliable yet. The method recommended in this paper is feasible to learn the localized reliabilities revealed from monitored data of a long-term SHM system of bridges, which would help bridge engineers and managers to decide a bridge inspection or maintenance strategy.

Statistics and probability analysis of vehicle overloads on a rigid frame bridge from long-term monitored strains

Liqun Tang,Yinghua Li,Zejia Liu,Yiping Liu 국제구조공학회 2012 Smart Structures and Systems, An International Jou Vol.9 No.3

It is well known that overloaded vehicles may cause severe damages to bridges, and how to estimate and evaluate the status of the overloaded vehicles passing through bridges become a challenging problem. Therefore, based on the monitored strain data from a structural health monitoring system (SHM) installed on a bridge, a method is recommended to identify and analyze the probability of overloaded vehicles. Overloaded vehicle loads can cause abnormity in the monitored strains, though the abnormal strains may be small in a concrete continuous rigid frame bridge. Firstly, the abnormal strains are identified from the abundant strains in time sequence by taking the advantage of wavelet transform in abnormal signal identification;secondly, the abnormal strains induced by heavy vehicles are picked up by the comparison between the identified abnormal strains and the strain threshold gotten by finite element analysis of the normal heavy vehicle; finally, according to the determined abnormal strains induced by overloaded vehicles, the statistics of the overloaded vehicles passing through the bridge are summarized and the whole probability of the overloaded vehicles is analyzed. The research shows the feasibility of using the monitored strains from a longterm SHM to identify the information of overloaded vehicles passing through a bridge, which can help the traffic department to master the heavy truck information and do the damage analysis of bridges further.

Study on the measurement accuracy of circular transmission line model for low-resistance Ohmic contacts on III-V wide band-gap semiconductors

Tong Liu,Rong Huang,Fangsen Li,Zengli Huang,Jian Zhang,Jianping Liu,Liqun Zhang,Shuming Zhang,An Dingsun,Hui Yang 한국물리학회 2018 Current Applied Physics Vol.18 No.7

The accuracy and error propagation for determining the low specific contact resistance of Ohmic contacts on IIIV wide band-gap semiconductors based on the circular transmission line model have been analyzed and the validity of this method is discussed in detail. The accuracy is more susceptible to the factors including data fitting method, electrical measurement technique and contact area correction. By using the equations of the original circular transmission line model to extract the fitting parameters, the calculation accuracy is much improved and the inapplicability of the linear least-square fitting is prevented. To further improve the accuracy, a four-probe current-voltage measurement technique was adopted to reduce the parasitic series resistances and the uncertainty bound, especially for the Ohmic contact with low sheet resistance of the semiconductor. Moreover, we have studied the size effect of contact pads of patterns and demonstrated that contact area correction is necessary for the semiconductor with high sheet resistance. A comprehensive error analysis is also performed to fully understand all the impact factors on this advanced method of specific contact resistance measurement, which is benefit for device performance evaluation and failure analysis.

Localized reliability analysis on a large-span rigid frame bridge based on monitored strains from the long-term SHM system

Zejia Liu,Liqun Tang,Yinghua Li,Yiping Liu,Zhenyu Jiang,Daining Fang 국제구조공학회 2014 Smart Structures and Systems, An International Jou Vol.14 No.2

With more and more built long-term structural health monitoring (SHM) systems, it has been considered to apply monitored data to learn the reliability of bridges. In this paper, based on a long-term SHM system, especially in which the sensors were embedded from the beginning of the construction of the bridge, a method to calculate the localized reliability around an embedded sensor is recommended and implemented. In the reliability analysis, the probability distribution of loading can be the statistics of stress transferred from the monitored strain which covered the effects of both the live and dead loads directly, and it means that the mean value and deviation of loads are fully derived from the monitored data. The probability distribution of resistance may be the statistics of strength of the material of the bridge accordingly. With five years\' monitored strains, the localized reliabilities around the monitoring sensors of a bridge were computed by the method. Further, the monitored stresses are classified into two time segments in one year period to count the loading probability distribution according to the local climate conditions, which helps us to learn the reliability in different time segments and their evolvement trends. The results show that reliabilities and their evolvement trends in different parts of the bridge are different though they are all reliable yet. The method recommended in this paper is feasible to learn the localized reliabilities revealed from monitored data of a long-term SHM system of bridges, which would help bridge engineers and managers to decide a bridge inspection or maintenance strategy

Kinetics of transesterification of methyl acetate and n-octanol catalyzed by cation exchange resins

Yong Liu,Min Wei,Li Gao,Xiying Li,Liqun Mao 한국화학공학회 2013 Korean Journal of Chemical Engineering Vol.30 No.5

The transesterification kinetics of methyl acetate with n-octanol to octyl acetate and methanol were studied using Amberlyst 15 as catalyst in a batch stirred reactor. The influence of the agitation speed, particle size, temperature,catalyst loading, and initial reactants molar ratio was investigated in detail. A pseudo-homogeneous (PH) kinetic model was applied to correlate the experimental data in the temperature range of 313.15 K to 328.15 K. The estimated kinetic parameters made the calculated results in good agreement with the experimental data. A kinetic model describing the transesterification reaction catalyzed by cation exchange resins was developed.

Fishbone Oscillations in the Experimental Advanced Superconductivity Tokamak

Liqing Xu,Liqun Hu,Yi Yuan,Yingying Li,Guo-Qiang Zhong,Hai-Qing Liu,Kaiyun Chen,Tong-Hui Shi,Yan-Min Duan 한국물리학회 2018 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.72 No.6

A fishbone oscillation was observed in the neutral beam injection plasma at Experimental Ad- vanced Superconductivity Tokamak (EAST). This m = 1/n = 1 (m, n: poloidal, toroidal mode numbers, respectively) typical internal kink mode travels in the ion-diamagnetism direction in the poloidal section with a rotation speed close to the ion diamagnetic drift frequency. A high thermal plasma beta and high amounts of energetic ions are necessary for the mode to develop. Fishbone oscillations can expel heavy impurities in the core, which favors sustaining a high-performance plasma. The born frequency of the fishbone oscillation is the ion diamagnetic drift frequency and the chirping down of the frequency during the initial growth phase is the result of a drop in ion- diamagnetic drift frequency. The excitation energy is thought to be due to the thermal plasma pressure gradient; however, the development of a fishbone oscillation is related to energetic ions. A fishbone oscillation was observed in the neutral beam injection plasma at Experimental Advanced Superconductivity Tokamak (EAST). This m = 1/n = 1 (m, n: poloidal, toroidal mode numbers, respectively) typical internal kink mode travels in the ion-diamagnetism direction in the poloidal section with a rotation speed close to the ion diamagnetic drift frequency. A high thermal plasma beta and high amounts of energetic ions are necessary for the mode to develop. Fishbone oscillations can expel heavy impurities in the core, which favors sustaining a high-performance plasma. The born frequency of the fishbone oscillation is the ion diamagnetic drift frequency and the chirping down of the frequency during the initial growth phase is the result of a drop in ion- diamagnetic drift frequency. The excitation energy is thought to be due to the thermal plasma pressure gradient; however, the development of a fishbone oscillation is related to energetic ions.

Design and Implementation of Paper Currency Sorting Process Management System

Bo Wang,Liqun Liu,Lin Qiu 보안공학연구지원센터 2014 International Journal of Control and Automation Vol.7 No.2

高中文言文虛詞知識點分佈測查及教學啟示 : 基於人教社課標本教材

Lv Siqi,Liu Liqun 단국대학교 한문교육연구소 2020 International Han-character Education Research Vol.2 No.1

고문 교육에 있어서 허사는 가장 중요한 부분이자, 가장 어려운 부분이다. 본문은 인민교육출 판사의 『普通高中課程標準實驗教科書(必修)』에 수록된 고문을 대상으로, 현재 고등학교의 고 문 교육과 평가 영역에서 다루는 18종의 주요 허사의 의미 분포와 주석 양상에 대해 전면적인 통계 분석을 진행하고, 그 분석 결과를 바탕으로 고문 허사 교수법에 대한 몇 가지 의견을 제시하 였다. 이를 통해 고문의 허사 교육이 과학적이고 체계적인 방향으로 발전하기를 기대해 본다. Function words are the key and difficult points in classical Chinese teaching. In this paper, the author takes the classical chinese materials from the standard experimental textbook (compulsory) of senior high school printed by People's Education Press as the research object. A comprehensive statistics on and analysis of 18 key function words distributed and noted in the textbook during teaching and tests were taken. Based on the results, some practical suggestions on the teaching of classical Chinese function words are put forward in order to promote the scientific and systematic development of the teaching of classical Chinese functional words.

Synthesis and photoelectrochemical behavior of CdS quantum dots-sensitized indium–tin–oxide mesoporous film

Haining Chen,Liqun Zhu,Weiping Li,Huicong Liu 한국물리학회 2012 Current Applied Physics Vol.12 No.1

In this paper, we reported an investigation on a new photoelectrode of quantum dots-sensitized solar cell (QDSC) combining indiumetineoxide (ITO) mesoporous film and CdS quantum dots (QDs). The ITO mesoporous film was prepared by doctor-blade technique and CdS QDs attached on ITO mesoporous film were synthesized by successive ionic layer adsorption and reaction method. X-ray diffraction, field emission scanning electron microscopy, transmission electron microscope, X-ray spectroscopy and UV evis spectroscopy were used to characterize the samples. The results indicated that the ITO mesoporous film was uniform, crack-free and highly porous. And absorbance in visible region was enhanced after the deposition of CdS QDs on ITO mesoporous film. The photoelectrochemical property of the CdS QDssensitized ITO mesoporous film photoelectrode was investigated by forming a photoelectrochemical cell. Photocurrentevoltage measurement showed that the photoelectrode was efficient in the cell as working electrode.

Rapid Detection of Clostridium tetani by Recombinase Polymerase Amplification Using an Exo Probe

( Mingjing Guo ),( Pan Feng ),( Liqun Zhang ),( Chunfeng Feng ),( Jie Fu ),( Xiaoyun Pu ),( Fei Liu ) 한국미생물 · 생명공학회 2022 Journal of microbiology and biotechnology Vol.32 No.1

Tetanus is a potentially fatal public health illness resulted from the neurotoxins generated by Clostridium tetani. C. tetani is not easily culturable and culturing the relevant bacteria from infected wounds has rarely been useful in diagnosis; PCR-based assays can only be conducted at highly sophisticated laboratories. Therefore, a real-time recombinase polymerase amplification assay (Exo-RPA) was constructed to identify the fragments of the neurotoxin gene of C. tetani. Primers and the exo probe targeting the conserved region were designed, and the resulting amplicons could be detected in less than 20 min, with a detection limit of 20 copies/reaction. The RPA assay displayed good selectivity, and there were no cross-reactions with other infectious bacteria common in penetrating wounds. Tests of target-spiked serum and pus extract revealed that RPA is robust to interfering factors and has great potential for further development for biological sample analysis. This method has been confirmed to be reliable for discriminating between toxic and nontoxic C. tetani strains. The RPA assay dramatically improves the diagnostic efficacy with simplified device architecture and is a promising alternative to real-time PCR for tetanus detection.