Tianjin University of Technology is a university in Tianjin, China under the municipal government. It is a public university approved by the State Council in 1981. As an engineering based multi-discipline university, it now has over 16,000 students, 988 teaching faculty and offers 45 Bachelor programs and 39 Master programs in areas such as science, engineering, humanities and management on 2 campuses. Wikipedia.
Zhao N.,Tianjin University of Technology
Nature Photonics | Year: 2015
Increasing the information capacity per unit bandwidth has been a perennial goal of scientists and engineers. Multiplexing of independent degrees of freedom, such as wavelength, polarization and more recently space, has been a preferred method to increase capacity in both radiofrequency and optical communication. Orbital angular momentum, a physical property of electromagnetic waves discovered recently, has been proposed as a new degree of freedom for multiplexing to achieve capacity beyond conventional multiplexing techniques, and has generated widespread and significant interest in the scientific community. However, the capacity of orbital angular momentum multiplexing has not been established or compared to other multiplexing techniques. Here, we show that orbital angular momentum multiplexing is not an optimal technique for realizing the capacity limits of a free-space communication channel and is outperformed by both conventional line-of-sight multi-input multi-output transmission and spatial-mode multiplexing. © 2015 Nature Publishing Group
Liang M.,Tianjin University of Technology |
Liang M.,Nankai University |
Chen J.,Nankai University
Chemical Society Reviews | Year: 2013
Arylamine organic dyes with donor (D), π-bridge (π) and acceptor (A) moieties for dye-sensitized solar cells (DSCs) have received great attention in the last decade because of their high molar absorption coefficient, low cost and structural variety. In the early stages, the efficiency of DSCs with arylamine organic dyes with D-π-A character was far behind that of DSCs with ruthenium(ii) complexes partly due to the lack of information about the relationship between the chemical structures and the photovoltaic performance. However, exciting progress has been recently made, and power conversion efficiencies over 10% were obtained for DSCs with arylamine organic dyes. It is thus that the recent research and development in the field of arylamine organic dyes employing an iodide/triiodide redox couple or polypyridyl cobalt redox shuttles as the electrolytes for either DSCs or solid-state DSCs has been summarized. The cell performance of the arylamine organic dyes are compared, providing a comprehensive overview of arylamine organic dyes, demonstrating the advantages/disadvantages of each class, and pointing out the field that needs to reinforce the research direction in the further application of DSCs. © 2013 The Royal Society of Chemistry.
Xiao S.,Macau University of Science and Technology |
Li Y.,Tianjin University of Technology
IEEE Transactions on Industrial Electronics | Year: 2013
This paper presents the optimal design, fabrication, and control of a novel compliant flexure-based totally decoupled XY micropositioning stage driven by electromagnetic actuators. The stage is constructed with a simple structure by employing double four-bar parallelogram flexures and four noncontact types of electromagnetic actuators to realize the kinematic decoupling and force decoupling, respectively. The kinematics and dynamics modeling of the stage are conducted by resorting to compliance and stiffness analysis based on matrix method, and the parameters are obtained by multiobjective genetic algorithm (GA) optimization method. The analytical models for electromagnetic forces are also established, and both mechanical structure and electromagnetic models are validated by finite-element analysis via ANSYS software. It is found that the system is with hysteresis and nonlinear characteristics when a preliminary open-loop test is conducted; thereafter, a simple PID controller is applied. Therefore, an inverse Preisach model-based feedforward sliding-mode controller is exploited to control the micromanipulator system. Experiments show that the moving range can achieve 1 mm × 1 mm and the resolution can reach ± 0.4μm. Moreover, the designed micromanipulator can bear a heavy load because of its optimal mechanical structure. © 1982-2012 IEEE.
Gong J.,Tianjin University of Technology
Chemical Reviews | Year: 2012
A study was conducted to investigate structure and surface chemistry of gold-based model catalysts. The study started with an overview of surface structures and electronic properties of various gold (Au) single-crystal surfaces. It examined adsorption phenomena on Au macroscopic crystalline surfaces under the investigations. Investigations revealed that gold crystallized as a face-centered cubic (fcc) structure where three low Miller indexed surfaces, such as 100, 110, and 111 were considered. The 111 facet of gold had the lowest surface energy among other surfaces, as reflected in the growing tendency for thin film in the  direction. It had the highest ductility and malleability of any element, and was the only metal for which the close-packed surface of an fcc crystal had been observed to reconstruct, which was attributed to relativistic effects in the large electronic core of gold.
Li S.,Tianjin University of Technology |
Gong J.,Tianjin University of Technology
Chemical Society Reviews | Year: 2014
Owing to the considerable publicity that has been given to petroleum related economic, environmental, and political problems, renewed attention has been focused on the development of highly efficient and stable catalytic materials for the production of chemical/fuel from renewable resources. Supported nickel nanoclusters are widely used for catalytic reforming reactions, which are key processes for generating synthetic gas and/or hydrogen. New challenges were brought out by the extension of feedstock from hydrocarbons to oxygenates derivable from biomass, which could minimize the environmental impact of carbonaceous fuels and allow a smooth transition from fossil fuels to a sustainable energy economy. This tutorial review describes the recent efforts made toward the development of nickel-based catalysts for the production of hydrogen from oxygenated hydrocarbons via steam reforming reactions. In general, three challenges facing the design of Ni catalysts should be addressed. Nickel nanoclusters are apt to sinter under catalytic reforming conditions of high temperatures and in the presence of steam. Severe carbon deposition could also be observed on the catalyst if the surface carbon species adsorbed on metal surface are not removed in time. Additionally, the production of hydrogen rich gas with a low concentration of CO is a challenge using nickel catalysts, which are not so active in the water gas shift reaction. Accordingly, three strategies were presented to address these challenges. First, the methodologies for the preparation of highly dispersed nickel catalysts with strong metal-support interaction were discussed. A second approach - the promotion in the mobility of the surface oxygen - is favored for the yield of desired products while promoting the removal of surface carbon deposition. Finally, the process intensification via the in situ absorption of CO2 could produce a hydrogen rich gas with low CO concentration. These approaches could also guide the design of other types of heterogeneous base-metal catalysts for high temperature processes including methanation, dry reforming, and hydrocarbon combustion. © 2014 the Partner Organisations.