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Investigating Foreign Language Education through the Lenses of Great Minds
Yang Gao
English Language Teaching , 2013, DOI: 10.5539/elt.v6n3p104
Abstract: The paper is a brief review of three great philosophers’ tenetsand their implications on foreign language education. Based on the recurring themes, namely, Noddings “teaching with care”, Dewey’s “learning by doing” and Vygotsky’s sociocultural theory, the paper highlights the importance of care and love, interaction, practical opportunities and scaffolding in a foreign language classroom, and gives insights on teaching, learning and curriculum design in foreign language education. Leaners in a foreign language classroom may be more struggling with their learning, thus requiring more care and help from their teachers. These philosophies serve as guiding principles to help teachers understand the meaning of their teaching and explore the world of foreign language education.
Hierarchical Coordinated Control for Power System Voltage Using Linear Temporal Logic  [PDF]
Hongshan ZHAO, Hongliang GAO, Yang XIA
Engineering (ENG) , 2009, DOI: 10.4236/eng.2009.12014
Abstract: The paper proposed an approach to study the power system voltage coordinated control using Linear Temporal Logic (LTL). First, the hybrid Automata model for power system voltage control was given, and a hierarchical coordinated voltage control framework was described in detail. In the hierarchical control structure, the high layer is the coordinated layer for global voltage control, and the low layer is the power system controlled. Then, the paper introduced the LTL language, its specification formula and basic method for control. In the high layer, global voltage coordinated control specification was defined by LTL specification formula. In order to implement system voltage coordinated control, the LTL specification formula was transformed into hybrid Automata model by the proposed algorithms. The hybrid Automata in high layer could coordinate the different distributed voltage controller, and have constituted a closed loop global voltage control system satisfied the LTL specification formula. Finally, a simple example of power system voltage control include the OLTC controller, the switched capacitor controller and the under-voltage shedding load controller was given for simulating analysis and verification by the proposed approach for power system coordinated voltage control. The results of simulation showed that the proposed method in the paper is feasible.
Tribological Behavior of Stellite 720 Coating under Block-on-Ring Wear Test  [PDF]
Rong Liu, Qi Yang, Feng Gao
Materials Sciences and Applications (MSA) , 2012, DOI: 10.4236/msa.2012.311110
Abstract: Stellite 720 is a high-carbon Co-Cr-Mo alloy, designed for severe wear/corrosion environments. This article presents a study of the Stellite 720 coating on stainless steel 304 under block-on-ring wear test. The coating is deposited through a slurry/powder metallurgy sintering process. Micro-hardness indentation test is conducted on the cross section of the coating specimen to investigate the hardness of individual phases of the coating material and the dilution effect of the substrate material on the coating layer. The tribological behavior of the coating under low and high load wear is investigated. The worn surfaces of the coating specimens are analyzed using a Philips XL30S FEG scanning electron micro- scope (SEM) with an EDAX energy dispersive X-ray (EDX) spectroscopy system. The experimental results are discussed to explore the wear mechanisms of the Stellite 720 coating under block-on-ring wear.
Synthesis, Photochromic Property and Application for Optical Recording of a New Asymmetrical Diarylethene  [PDF]
Huirong Du, Shangfen Gao, Li Yang
International Journal of Organic Chemistry (IJOC) , 2012, DOI: 10.4236/ijoc.2012.24053
Abstract: The reversible molecule switching of an assymmetrical photochromic diarylethene 1-[2-methy1-5-(3-chlorophenyl)-3-thienyl]-2-(1,2-dimethy1-3-indol) perfluorocyelopentene (1a) has been prepared for the examination of photo-switching, fluorescence switching. This compound exhibited reversible photochromism, changing from colorless to blue after irradiation with UV light both in solution and in poly-methyl methacrylate (PMMA) amorphous film. Also, it exhibited remarkable fluorescence switching in the solid state. Using diarylethene 1b/PMMA film as recording medium, polarization optical recording was performed perfectly by a He-Ne laser with 633 nm wavelength. The results demonstrated that it can be potentially used as polarization optical recording medium.
Existence and Uniqueness of Solutions to Impulsive Fractional Integro-Differential Equations with Nonlocal Conditions  [PDF]
Zhenghui Gao, Liu Yang, Gang Liu
Applied Mathematics (AM) , 2013, DOI: 10.4236/am.2013.46118
Abstract: In this article, by using Schaefer fixed point theorem, we establish sufficient conditions for the existence and uniqueness of solutions for a class of impulsive integro-differential equations with nonlocal conditions involving the Caputo fractional derivative.
Enhanced Bilinear Approach for Sensor Network Self-Localization Using Noisy TOF Measurements  [PDF]
Xue Gao, Le Yang, Li Peng
Journal of Computer and Communications (JCC) , 2014, DOI: 10.4236/jcc.2014.27004
Abstract:

This paper develops a new algorithm for sensor network self-localization, which is an enhanced version of the existing Crocco’s method in [11]. The algorithm explores the noisy time of flight (TOF) measurements that quantify the distances between sensor nodes to be localized and sources also at unknown positions. The newly proposed technique first obtains rough estimates of the sensor node and source positions, and then it refines the estimates via a least squares estimator (LSE). The LSE takes into account the geometrical constraints introduced by the desired global coordinate system to improve performance. Simulations show that the new technique offers superior localization accuracy over the original Crocco’s algorithm under small measurement noise condition.

Error and Performance Analysis of MEMS-based Inertial Sensors with a Low-cost GPS Receiver
Minha Park,Yang Gao
Sensors , 2008, DOI: 10.3390/s8042240
Abstract: Global Navigation Satellite Systems (GNSS), such as the Global Positioning System (GPS), have been widely utilized and their applications are becoming popular, not only in military or commercial applications, but also for everyday life. Although GPS measurements are the essential information for currently developed land vehicle navigation systems (LVNS), GPS signals are often unavailable or unreliable due to signal blockages under certain environments such as urban canyons. This situation must be compensated in order to provide continuous navigation solutions. To overcome the problems of unavailability and unreliability using GPS and to be cost and size effective as well, Micro Electro Mechanical Systems (MEMS) based inertial sensor technology has been pushing for the development of low-cost integrated navigation systems for land vehicle navigation and guidance applications. This paper will analyze the characterization of MEMS based inertial sensors and the performance of an integrated system prototype of MEMS based inertial sensors, a low-cost GPS receiver and a digital compass. The influence of the stochastic variation of sensors will be assessed and modeled by two different methods, namely Gauss-Markov (GM) and AutoRegressive (AR) models, with GPS signal blockage of different lengths. Numerical results from kinematic testing have been used to assess the performance of different modeling schemes.
Inertial Aided Cycle Slip Detection and Identification for Integrated PPP GPS and INS
Shuang Du,Yang Gao
Sensors , 2012, DOI: 10.3390/s121114344
Abstract: The recently developed integrated Precise Point Positioning (PPP) GPS/INS system can be useful to many applications, such as UAV navigation systems, land vehicle/machine automation and mobile mapping systems. Since carrier phase measurements are the primary observables in PPP GPS, cycle slips, which often occur due to high dynamics, signal obstructions and low satellite elevation, must be detected and repaired in order to ensure the navigation performance. In this research, a new algorithm of cycle slip detection and identification has been developed. With the aiding from INS, the proposed method jointly uses WL and EWL phase combinations to uniquely determine cycle slips in the L1 and L2 frequencies. To verify the efficiency of the algorithm, both tactical-grade and consumer-grade IMUs are tested by using a real dataset collected from two field tests. The results indicate that the proposed algorithm can efficiently detect and identify the cycle slips and subsequently improve the navigation performance of the integrated system.
Progress in fabricating arrays of soft spherical vessels on mesoscale with spatial control
Jie Yang,ChangYou Gao
Chinese Science Bulletin , 2008, DOI: 10.1007/s11434-008-0485-0
Abstract: Microarrays of spherical vessel-like colloids such as liposomes, polymerized vesicles and polyelectrolyte capsules may find diverse applications in bioanalysis, biosensing, and combinatorial chemistry, for their capabilities in encapsulating chemical species such as drugs, biomolecules, probes, polymers and nanoparticles. This review reports the advances on methods for fabricating microarrays of the various hollow colloids. Related strategies are described in detail, including patterning techniques, surface modification methods, and tethering approaches such as oligonucleotide hybridization, receptor-ligand binding, covalent coupling and electrostatic interaction. The preliminary developments of functionalities of these arrays serving as sensor chips, microcarriers and microreactors are summarized as well.
Agrobacterium tumefaciens-mediated transformation ofCry I A(b) gene toTrichoderma harzianum
Xingxi Gao,Qian Yang
Chinese Science Bulletin , 2004, DOI: 10.1007/BF03183720
Abstract: In this study,Cry IA(b) gene was successfully transferred into the biocontrol fungusTrichoderma harzianum with an efficiency of 60–180 transformants per 106 spores by usingAgrobacterium tumefaciens-mediated transformation. Putative transformants were analyzed to test the presence ofCry IA(b) gene by Southern blot. Most transformants contained a single T-DNA copy. RT-PCR analysis showed that theCry IA(b) gene was transcribed. Antifungal activities and insecticidal activities of the transformants were examined. There was no obvious difference in antifungal activities between the transformants and their wild strains. The modified mortalities of the transformants T1 and T2 were 69.57% and 91.30%, respectively. The tranformation system mediated byA. tumefaciens proved to be a powerful tool for the filamentous fungi transformation and functional genomic study with its high transformation frequency, simplicity of T-DNA integration, and genetic stability of transformants.
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