A Simulation Study on the Impact of Abandoned Trolley Cases on Pedestrian Evacuation

Dongyue Xu,Jinghong Wang,Juan Liu,Yan Wang,Juncheng Jiang 대한토목학회 2023 KSCE JOURNAL OF CIVIL ENGINEERING Vol.27 No.3

Many pedestrians empirically think that discarding luggage can improve evacuation efficiency, but it is unclear whether discarding luggage is an effective evacuation strategy. Previous models also oversimplified the interference of abandoned luggage on pedestrians. Hence, an extended social force model integrates pedestrian interaction with abandoned luggage like trolley cases was firstly proposed. A simulation based on a real metro station was carried out to examine the effectiveness of evacuation strategy like abandoning trolley cases at the bottleneck such as gate machine and metro carriage door, and the influence mechanism of abandoned trolley cases on pedestrians was investigated. The results show that discarding the trolley cases at the gate machine and at the metro carriage door cannot improve evacuation efficiency but increase the evacuation time by 78.7% and 14.9% at these two positions when the carrying ratio is 50%, respectively. When the occupancy rate of trolley case at the gate machine and metro carriage door is below 19% and 11%, pedestrians tend to detour the abandoned trolley cases and this behavior significantly increased the collisions between pedestrians at bottlenecks, and when the occupancy rate exceeds, they tend to push aside the trolley cases and the evacuation efficiency is further reduced.

Electromechanical properties of 2-2 cement based piezoelectric composite

Xu Dongyu,Cheng Xin,Huang Shifeng,Jiang Minhua 한국물리학회 2009 Current Applied Physics Vol.9 No.4

A 2-2 type cement based piezoelectric composites were fabricated by dice-and-fill technique. The influences of lead magnesium niobate-lead zirconate-lead titanate (PMN) ceramic volume fraction on the electromechanical properties of the composite were investigated. The results indicate that the planar electromechanical coupling factor Kp of the composite is hardly influenced by the PMN volume fraction, which fluctuates between 35% and 37%, while both the thickness electromechanical coupling factor Kt and the mechanical quality factor Qm exhibit the trend of increase. When PMN volume fraction is 69.2%, Kt could reach to 49.8%, which is larger than that of the PMN ceramic (Kt = 46%).When PMN volume fraction is 41.7%, Qm is 4.5, which is also much less than that of the PMN ceramic (Qm = 70). This means that the composite has wider frequency band and higher sensitivity to be used as transducers. With the increase of PMN volume fraction, the acoustic impedance of the composite also exhibits the trend of increase. A 2-2 type cement based piezoelectric composites were fabricated by dice-and-fill technique. The influences of lead magnesium niobate-lead zirconate-lead titanate (PMN) ceramic volume fraction on the electromechanical properties of the composite were investigated. The results indicate that the planar electromechanical coupling factor Kp of the composite is hardly influenced by the PMN volume fraction, which fluctuates between 35% and 37%, while both the thickness electromechanical coupling factor Kt and the mechanical quality factor Qm exhibit the trend of increase. When PMN volume fraction is 69.2%, Kt could reach to 49.8%, which is larger than that of the PMN ceramic (Kt = 46%).When PMN volume fraction is 41.7%, Qm is 4.5, which is also much less than that of the PMN ceramic (Qm = 70). This means that the composite has wider frequency band and higher sensitivity to be used as transducers. With the increase of PMN volume fraction, the acoustic impedance of the composite also exhibits the trend of increase.

High-performance hybrid white organic light-emitting diodes employing p-type interlayers

Baiquan Liu,Hong Tao,Jianhua Zou,Miao Xu,Dongyu Gao,Linfeng Lan,Lei Wang,Honglong Ning,Junbiao Peng 한국공업화학회 2015 Journal of Industrial and Engineering Chemistry Vol.27 No.-

A simplified hybrid white organic light-emitting diode (WOLED) employing a p-type interlayer isdesigned, simultaneously realizing high efficiency, high color rendering index (CRI), low efficiency roll-off, low voltage and stable color. The device exhibits maximum total efficiencies of 29.8 cd/A and20.9 lm/W, which slightly decrease to 28.6 cd/A and 16.5 lm/W even at a high luminance of 5000 cd/m2. Besides, a slight color-shift and a CRI of 85 at 100 cd/m2 (3.65 V) are obtained. Such superior resultssystematically demonstrate that the use of p-type interlayer is a new way to realize high-performancehybrid WOLEDs.

Effect of carbon black on properties of 0–3 piezoelectric ceramic/cement composites

Huang Shifeng,Li Xue,Liu Futian,Chang Jun,Xu Dongyu,Cheng Xin 한국물리학회 2009 Current Applied Physics Vol.9 No.6

0–3 cement-based piezoelectric composites were fabricated using sulphoaluminate cement and piezoelectric ceramic [0.08Pb(Li1/4Nb3/4)O3 . 0.47PbTiO3 . 0.45PbZrO3] [P(LN)ZT] as raw materials by compressing technique. The influences of carbon black content on the piezoelectric and dielectric properties, electric conductivity and impedance were investigated. The results indicate that the piezoelectric strain constant d33 and piezoelectric voltage constant g33 of the composites increase gradually with a suitable carbon black addition. When the carbon black content is 0.3 wt%, both of the piezoelectric strain constant d33 and piezoelectric voltage constant g33 of the composite exist the maximum value, which are 17.45 pC N-1 and 36.3 mV m N-1, respectively. As the carbon black content increases, the dielectric constant εr, dielectric loss tanδ and electric conductivity σ of the composites all increase, while the impedance decreases. In the frequency range tested, the more the carbon black content, the higher the εr value. The planar electromechanical coupling coefficient Kp, the thickness electromechanical coupling coefficient Kt and the mechanical quality factor Qm are almost unaffected by the carbon black content.

Efficient single-emitting layer hybrid white organic light-emitting diodes with low efficiency roll-off, stable color and extremely high luminance

Baiquan Liu,Honglong Ning,Lei Wang,Jianhua Zou,Zhongwei Zhou,Miao Xu,Hong Tao,Dongyu Gao,Linfeng Lan,Junbiao Peng 한국공업화학회 2015 Journal of Industrial and Engineering Chemistry Vol.30 No.-

An efficient single-emitting layer hybrid white organic light-emitting diode (WOLED) was developed,simultaneously fulfilling low efficiency roll-off, stable color and extreme luminance. At the practicalluminance of 1000 cd/m2, a total current efficiency of 42.8 cd/A and power efficiency of 19.2 lm/W areachieved, maintaining as high as 40.5 cd/A and 15.5 lm/W even at 5000 cd/m2. Besides, a slight colorvariation [(0.025, 0.011)] and extreme luminance ( 106 cd/m2) are obtained. The working mechanism isunveiled and it is demonstrated that the triplet-exciton-confining ability of electron transport layersplays a more vital role in device performances, particularly for the lifetime.

Equilibrium, kinetic and mechanism studies on the biosorption of Cu2+ and Ni2+ by sulfur-modified bamboo powder

Tian Ai,Xiaojun Jiang,Hongmei Yu,Hong-Bo Xu,Dawei Pan,Qingyu Liu,Dongyu Chen,Jinyang Li 한국화학공학회 2015 Korean Journal of Chemical Engineering Vol.32 No.2

Two biosorbents were prepared using bamboo powder modified with mercaptoacetic acid and carbondisulfide, which exhibits strong adsorption properties for Cu2+ and Ni2+. The obtained materials were characterized byFTIR. Maximum adsorption for both metals was found to occur around pH 5.0-6.5. The kinetic data followed thepseudo-second-order model. The maximum adsorption capacities of Cu2+ and Ni2+ on mercaptoacetic acid modifiedbamboo powder determined from Langmuir isotherm were 103.97mg g−1 and 61.35mg g−1, respectively. While oncarbon disulfide modified bamboo powder were 128.21mg g−1 and 56.82mg g−1, respectively. The adsorption mechanismanalysis revealed that the most possible adsorption mode of Cu2+ was coordination, and Ni2+ was ion exchange. The obtained adsorbents could effectively remove Cu2+ and Ni2+ from industrial electroplating wastewater and could beused repeatedly for more than five cycles.