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Abstrakt

Tunnel lay-by spacing is directly related to traffic safety and engineering investment. Nevertheless, its mechanism is not clear, and the rationality of the exiting norms with respect to tunnel lay-by spacing needs to demonstrate. A calculation model for tunnel lay-by spacing was derived by considering the headway and the physical kinematics of the two vehicles chasing and encountering. With it, the influence of various parameters on lay-by spacing were analysed and the rationality of the model were discussed through comparing with existing norms. Results shows longitudinal gradient rate, daily average traffic flow, rolling resistance coefficient, posted speed limit are significant to determine the lay-by spacing, and the most important parameter is longitudinal gradient rate. Existing tunnel lay-by spacing norm values are not reasonable enough, either too strict or too loose. These findings provide scientific support for how to select tunnel lay-by spacing value, which can improve tunnel traffic safety and make engineering investment reasonable.
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Autorzy i Afiliacje

Bo Liang
1
ORCID: ORCID
Yao Xiao
2
ORCID: ORCID

  1. Chongqing Jiaotong University, School of Civil Engineering, State Key Laboratory of Mountain Bridge and Tunnel Engineering, Xuefu Avenue 66, Nanan District, Chongqing, China
  2. Chongqing Jiaotong University, School of Civil Engineering, Chongqing Rail Transit (Group) Co., Ltd, Xuefu Avenue 66, Nanan District, Chongqing, China

Abstrakt

In recent years, some expressway tunnels have started broadcasting warning sounds, such as fire alarms, to improve driver attention and traffic safety. However, there is few research on it, and in contrast to previous studies, we have considered different evaluation indices and through field measurement to determine the effectiveness of this practice. The characteristics of three warning sound signals, i.e., fire alarm, dynamic music, and voice command, in a tunnel were analyzed usingMATLAB. Considering pupil diameter and blink duration as evaluation indexes, the change in the mental state of the driver after hearing a warning sound was analyzed. Based on Markov chain theory, the change in the gaze region and gaze shift of the driver under the condition of a warning sound was analyzed. Results shows fire alarms and voice commands can increase the mental load of drivers, but the degree of impact was not determined. Dynamic music does not affect the mental load of the driver. The fire alarm and dynamic music attracted the attention of the driver; conversely, as the voice command warns the driver to focus on safety, it did not impact the attention of the driver. The research results provide a scientific reference for the selection of warning sounds in expressway tunnels and new research ideas for the prevention of traffic injuries in expressway tunnels.
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Autorzy i Afiliacje

Yao Xiao
1
ORCID: ORCID
Bo Liang
2
ORCID: ORCID
Tao Wang
3
ORCID: ORCID
Jiaan Niu
4
ORCID: ORCID
Shiyong He
2
ORCID: ORCID

  1. Chongqing Jiaotong University, School of Civil Engineering, Chongqing Rail Transit (Group) Co., Ltd, Xuefu Avenue 66, Nanan District, Chongqing, China
  2. Chongqing Jiaotong University, School of Civil Engineering, State Key Laboratory of Mountain Bridge and Tunnel Engineering, Xuefu Avenue 66, Nanan District, Chongqing, China
  3. Chongqing Industrial School, Hualongqiong, Yuzhong District, Chongqing, China
  4. Chongqing Jiaotong University, School of Civil Engineering, Xuefu Avenue 66, Nanan District, Chongqing, China

Abstrakt

The microstructures and mechanical properties of T92 martensitic steel/Super304 austenitic steel weld joints with three welding consumables were investigated. Three types of welding materials ERNiCr-3, ERNiCrCoMo-1and T-304H were utilized to obtain dissimilar welds by using gas tungsten arc weld (GTAW). The results show that heat affect zone (HAZ) of T92 steel consists of coarse-grained and fine-grained tempered martensites. The microstructures of joints produced from ERNiCrCoMo-1 consist of equiaxed dendrite and columnar dendrite grains, which are more complicated than that of ERNiCr-3. In the tensile tests, joints constructed from ERNiCrCoMo-1 and T-304H met the ASME standard. The highest fracture energy was observed in specimens with the welding material ERNiCrCoMo-1. Ni content in weld seam of ERNiCrCoMo-1 was highest, which was above 40%. In conclusion, the nickel alloy ERNiCrCoMo-1 was the most suitable welding material for joints produced from T92 martensitic steel/Super304 austenitic steel.

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Autorzy i Afiliacje

Z. Liang
Y. Gui
Q. Zhao

Abstrakt

Magnetic-geared permanent magnet (MGPM) electrical machine is a new type of machine by incorporating magnetic gear into PM electrical machine, and it may be in operation with low-speed, high-torque and direct-driven. In this paper, three types of MGPM machines are present, and a quantitative comparison among them is performed by finite element analysis (FEA). The magnetic field distribution, stable torque and back EMF are obtained at no-load. The results show that three types of MGPM machine are suitable for different application fields respectively according to their own advantages, such as high torque and back EMF, which form an important foundation for MGPM electrical machine research.
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Autorzy i Afiliacje

Xiping Liu
Dong Chen
Liang Yi
Chao Zhang
Min Wang

Abstrakt

Temperature gradient zone melting (TGZM) method was used to obtain bulk Si continuously for the efficient separation and purification of primary Si from the Si-Al alloy in this work. The effects of alloy thickness, temperature gradient and holding time in TGZM purification technology were investigated. Finally, the continuous growth of bulk Si without eutectic inclusions was obtained. The results showed that the growth rate of bulk Si was independent of the liquid zone thickness. When the temperature gradient was changed from 2.48 K/mm to 3.97 K/mm, the growth rate of bulk Si was enhanced from 7.9×10–5 mm/s to 2.47×10–4 mm/s, which was increased by about 3 times. The bulk Si could grow continuously and the growth rate was decreased with the increase of holding time from 1 h to 5 h. Meanwhile, low refining temperature was beneficial to the removal of impurities. With a precipitation temperature of 1460 K and a temperature gradient of 2.48 K/mm, the removal rates of Fe, P and B were 99.8%, 94.0% and 63.6%, respectively.

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Autorzy i Afiliacje

Jiayan Li
Liang Wang
Jianjie Hao
Ping Ni
Yi Tan

Abstrakt

The data aggregation process of wireless sensor networks faces serious security problems. In order to defend the internal attacks launched by captured nodes and ensure the reliability of data aggregation, a secure data aggregation mechanism based on constrained supervision is proposed for wireless sensor network, which uses the advanced LEACH clustering method to select cluster heads. Then the cluster heads supervise the behaviors of cluster members and evaluate the trust values of nodes according to the communication behavior, data quality and residual energy. Then the node with the highest trust value is selected as the supervisor node to audit the cluster head and reject nodes with low trust values. Results show that the proposed mechanism can effectively identify the unreliable nodes, guarantee the system security and prolong the network lifetime.

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Autorzy i Afiliacje

Yubo Wang
Liang Li
Chen Ao
Puning Zhang
Zheng Wang
Xinyang Zhao

Abstrakt

To keep genetic diversity, flowering plants have developed a self-incompatibility system, which can prevent self-pollination.

It has been reported that calcium concentration in pistil papilla cells was increased after self-pollination

in transformed self-incompatible Arabidopsis thaliana. In this study, we found that CML27 changed its expression

level for both mRNA and protein when compared to transcriptome and proteome. At the same time, CML27 was

expressed in the anther and pistil at a high level and reached up to 5-fold up-regulated expression in the pistil

at 1 h post-pollination when compared to 0 min. In order to find out potential proteins that may interact with

BoCML27, BoCML27 was expressed in and isolated from E. coli. After its co-incubation with Brassica oleracea

pistil proteins, the products were separated on SDS-PAGE gels. We found a specific band at the position between

130–180 kDa. Through LC-MS-MS (Q-TOF) analysis, eight proteins were identified from the band. The proteins

include 26S proteasome non-ATPase regulatory (26S), Phospholipase D, alpha 2 (PLDα2) involved in Ca2+ binding

and Coatomer subunit alpha-2-like (Coatomer) involved in vesicle mediated transport. All of these identified

proteins provide new insights for the self-incompatibility response in B. oleracea, specific for increasing Ca2+

concentration in pistil papilla cells.

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Autorzy i Afiliacje

Xiao Ping Lian
Jing Zeng
He Cui Zhang
Xiao Hong Yang
Liang Zhao
Li Quan Zhu

Abstrakt

The paper presented the wavelet transform method for de-noising and singularity detection to soil compressive stress signal. The study results show that the reconstruction signals by the wavelet de-noising keeps the low frequency component at [0, 31.25 Hz] of the original signal and improves the high frequency property at other frequency bands. The impaction time from the start time to resonance time of the stress signals is varies with the depth of the soil. With the increase of times of compaction, the impaction time of the stress is decreasing in every layer. But the speed of reaching compacted status in each layer is different.

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Autorzy i Afiliacje

Zhang Qing-Zhe
Yan Bing
Dai Jing-Liang
Yang Bao-Gui

Abstrakt

Sapelovirus A (SV-A) is a positive-sense single-stranded RNA virus which is associated with acute diarrhea, pneumonia and reproductive disorders. The virus capsid is composed of four proteins, and the functions of the structural proteins are unclear. In this study, we expressed SV-A structural protein VP1 and studied its antigenicity and immunogenicity. SDS-PAGE analysis revealed that the target gene was expressed at high levels at 0.6 mM concentration of IPTG for 24 h. The mouse polyclonal antibody against SV-A VP1 protein was produced and reached a high antiserum titer (1: 2,048,000). Immunized mice sera with the recombinant SV-A VP1 protein showed specific recognition of purified VP1 protein by western blot assay and could recognize native SV-A VP1 protein in PK-15 cells infected with SV-A by indirect immunofluorescence assay. The successfully purified recombinant protein was able to preserve its antigenic determinants and the generated mouse anti-SV-A VP1 antibodies could recognize native SV-A, which may have the potential to be used to detect SV-A infection in pigs.

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Autorzy i Afiliacje

T.T. Zhao
L. Cui
L. Chen
J.J. Li
Q.L. Liang
P.J. Wu
X.Q. Yu
Z.H. Zhang
X.G. Hua

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