Tianjin Chengjian University

Tianjin, China

Tianjin Chengjian University

Tianjin, China
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This paper presents an optimization model for water quantity and quality integrated management of an urban lake in a water deficient city. A representative water quantity and quality safeguard system served urban lake, including multi-source water supply facilities, recirculating water purification facilities and surplus water discharge facilities, is widely used in Chinese water deficient cities. Because it is complicated, any mismanagement will result in water quality deterioration, water waste and high operation cost. The presented model attempts to achieve the objectives of controlling water pollution, reducing economic cost and improving water utilization efficiency through an optimized operating water safeguard system. The model is applied to Qingjing Lake in Tianjin, China. Results show that the model plays a more positive role for water quantity and quality integrated management. © 2017 Informa UK Limited, trading as Taylor & Francis Group

Wang L.,Tianjin Chengjian University
Agro Food Industry Hi-Tech | Year: 2017

The rapid development of internet transferred college students' traditional offline learning into network independent learning, which, however, still developed slowly. This paper intends to analyze college student's network independent learning with ID3 algorithm, showing the effectiveness and simplicity of ID3 algorithm by survey and analysis, which could not only produce accurate results, but also analyze the process. Thus, ID3 algorithm proved the availability of network independent English learning, as well as promoted the subjective initiative of students.

Lu X.,Tianjin Chengjian University | Liu Z.,Tianjin Chengjian University
Dalton Transactions | Year: 2017

In this paper, Co3O4 nanostructures with different morphologies (nanoparticles (NPs), nanosheets (NSs) and nanocubes (NCs)) are directly grown on an ITO substrate using a hydrothermal method. Sb2S3 is loaded onto Co3O4 to construct a Co3O4/Sb2S3 heterojunction, which is used as an all p-type photocathode for photoelectrochemical (PEC) water splitting for the first time. The specific morphologies of Co3O4 have been discussed in detail. The improved PEC properties of the Co3O4/Sb2S3 heterojunction are characterized. Among them, the outstanding photocurrent density of the Co3O4 NC/Sb2S3 heterojunction photocathode is accessed by -1.32 mA cm-2 at -0.4 V vs. RHE. The enhanced PEC properties result from more active sites of specific crystal planes, excellent optical performance, suitable band gradient alignment and increased charge separation and charge transfer rate. © 2017 The Royal Society of Chemistry.

Lv Y.,Tianjin Chengjian University
Journal of Vibroengineering | Year: 2017

Based on the secondary development of LS-DYNA program, the nonlinear dynamic p-y model and Bonora damage material model of steel were applied in the main program. Taking a four-span approach bridge as an example, the plastic damage model of the upper bridge and four simplified bridge pile-foundation models, including beam on Winkler foundation model, effective length pile model, total pile model considering soil-structure interaction (SSI) and no pile model, were introduced. The earthquake motions obtained by a free-field analysis were applied to the different depth of pile profile. The free vibration characteristics, displacement, internal force and damage under different levels of earthquake motions were analyzed. The stress-strain curve of different depth of p-y elements and pile deflection of Winkler-methods model were discussed. Analysis results indicated that the structure responses are different among the four pile-foundation models, the responses of the bridge in longitudinal and transverse directions are totally different, and the p-y model can be used to simulate the bridge precisely. © JVE INTERNATIONAL LTD. JOURNAL OF VIBROENGINEERING.

Lu X.,Tianjin Chengjian University | Liu Z.,Tianjin Chengjian University
Dalton Transactions | Year: 2017

A novel one-dimensional Co3O4/CuO/Ag composite structure film was directly grown on indium tin oxide glass substrate by a simple hydrothermal method and electrodeposition method. The film was employed for the first time as a photocathode for photoelectrochemical (PEC) water splitting to generate hydrogen. The photocurrent density of the Co3O4/CuO/Ag composite structure achieved -5.13 mA cm-2 at -0.2 V vs. RHE, which is roughly 12.8 times that of 1D Co3O4 nanowires and 3.31 times Co3O4/CuO heterojunction photocathodes. The enhanced PEC performance of this Co3O4/CuO/Ag composite structure ascribes increased light-harvesting and light-absorption, distensible photoresponse range, decreased interface charge transfer resistance, and improved photogenerated electron-hole pairs transfer and separation. © 2017 The Royal Society of Chemistry.

Pan L.,Tianjin Chengjian University
IEEE Transactions on Power Electronics | Year: 2014

On the basis of the classical Z-source inverter (ZSI), this paper presents a novel ZSI which only contains inductors and diodes in Z-source network. The inverter uses a unique inductor and diode network for boosting its output voltage, provides a common ground for the dc source and inverter, and avoids the disadvantage causing by capacitor in the classical ZSI and SL-ZSI, especially in prohibiting the inrush current at startup and the resonance of Z-source capacitors and inductors. The inverter can increase the boost factor through adjusting shoot-through duty ratio and increasing the number of inductor. The working principle of the proposed ZSI and comparison with the classical ZSI and SL-ZSI are analyzed in detail. Simulation and experimental results are given to demonstrate the operation features of the inverter. © 2014 IEEE.

Zhang Z.,Tianjin Chengjian University | Sun Z.,Tianjin Chengjian University | Duan C.,Tianjin Chengjian University
Energy and Buildings | Year: 2014

The heat transfer performance on the wall has a great influence on the energy conservation and the indoor thermal comfort. Once it can be adjustable according to the requirement, the wall can effectively regulate the indoor temperature, thereby directly reducing the building energy consumption. In this paper, a new type of passive solar energy utilization technology, the wall implanted with heat pipes (WIHP), was proposed, and its heat transfer performance and energy-saving characteristic were investigated theoretically and experimentally with the typical meteorological data of Jinan. The results indicate that the theoretical results agree well with experimental ones. The heat transfer performance of the WIHP is adjustable and controllable, which can reduce the heating load and improve thermal environment. During the winter in a typical year, the heat loss of the south external wall is reduced by 14.47%. Therefore, such a type of wall can apparently improve the indoor thermal environment, which can be popularized in engineering applications. © 2014 Elsevier B.V. All rights reserved.

Guo M.,Tianjin Chengjian University
RSC Advances | Year: 2014

The electronic structures and optical properties of C, Ag-codoped TiO2 were investigated within the GGA + U framework. Different doping concentration and different dopant distance (CsAgs (near and far), C2sAgs (near and far), and C3sAgs (near and far)) models were constructed. According to the formation energy results of these codoped systems, it was found that low concentration codoping was more stable than high concentration codoping. Therefore, we chose the CsAgs (near and far) codoped TiO2 to calculate further electronic structures and optical properties. It was found that near distance codoping could narrow the band gap to 2.81 eV, and far distance codoping decreased the band gap to 2.66 eV. Meanwhile, it was found that far distance codoping preferred to form more localized states near the top of the valence band, while near distance codoping could induce more significant hybrid states in the band gap. Optical property showed that C and Ag codoping could induce a synergistic effect compared with single C and single Ag doping. After codoping, the visible absorption was stronger for both the near and far distance codoped systems than those of the single doped systems, moreover, the far distance codoping configuration could induce both more significant band edge shift and stronger visible optical absorption than that of the near distance codoping configuration. This journal is © The Royal Society of Chemistry.

Guo G.,Dalian Maritime University | Zhao Y.,Dalian Maritime University | Yang G.,Tianjin Chengjian University
Information Sciences | Year: 2014

This paper investigates a minimum energy cooperation control problem in mobile sensor networks. Assuming a time-invariant undirected network topology for the sensors, we present a suboptimal solution that guarantees minimum overall energy cost of mobility and communication for the sensors to achieve consensus. The design procedure of the distributed control protocol is composed of two steps. The first step yields the local feedback gain via solving a linear quadratic regulating (LQR) problem, while the second step produces the network feedback gain based on convex optimization technique. The results are extended to formation control problems with and without communication delays. The effectiveness of the proposed methodology is illustrated by numerical examples. © 2013 Elsevier Inc. All rights reserved.

Liu Y.,Tianjin Chengjian University
Proceedings - 2015 2nd International Conference on Information Science and Control Engineering, ICISCE 2015 | Year: 2015

With the appearance of high speed WPA/WPA-PSK brute forcer, the security of WLAN faces serious threats. The attackers can acquire PSK easily so as to decrypt all the traffics. To solve this problem, a series of defence schemes are proposed, including defence schemes for passive and active brute forcers. The schemes adopt active jammer and wireless packet injection. And then the theoretical analysis is processed and the implementation methods are given. In the last past, the conclusions are reached. © 2015 IEEE.

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