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Chen A.,Beihang University | Chen A.,Leshan Vocational and Technical College | Zhu K.,Beihang University
Solar Energy | Year: 2012

The p-type a-Si:H/n-type c-Si (P + a-Si:H/N + c-Si) heterojunction was simulated for developing solar cells with high conversion efficiency and low cost. The characteristic of such cells with different work function of transparent conductive oxide (TCO) were calculated. The energy band structure, quantum efficiency and electric field are analyzed in detail to understand the mechanism of the heterojunction cell. Our results show that the a-Si/c-Si heterojunction is hypersensitive to the TCO work function, and the TCO work function should be large enough in order to achieve high conversion efficiency of P + a-Si:H/N + c-Si solar cells. With the optimized parameters set, the P + a-Si:H/N + c-Si solar cell reaches a high efficiency (η) up to 21.849% (FF: 0.866, V OC: 0.861V, J SC: 29.32mA/cm 2). © 2011 Elsevier Ltd.


Chen A.,Beihang University | Chen A.,Leshan Vocational and Technical College | Zhu K.,Beihang University
Solar Energy | Year: 2014

TCO/n-Si hetero-junction solar cells at present have low conversion efficiency although they have been fabricated for decades. In order to better understand the operation mechanism of such kind of cells and find possible solutions, the effect of the work function of transparent conducting oxide (TCO) on the performance of the TCO/n-Si hetero-junction cells was simulated. The band diagram, carrier lifetime and donor concentration in silicon layer were calculated. It is demonstrated that conversion efficiency, open circuit voltage and fill factor increase with the TCO work function. Analyzing band diagram of the TCO/n-Si hetero-junction indicates that the high TCO work function enhances the built-in potential resulting in the increase of open circuit voltage. Enhancement of the minority carrier lifetime in the interface at a higher TCO work function improves conversion efficiency. High interfacial defect density reduces the performance of the cells. It is suggested that increasing the TCO work function difference is a prospective solution to improve the performance of TCO/n-Si hetero-junction solar cells. © 2014 Elsevier Ltd.


Yang B.,Leshan Vocational and Technical College | Wang J.,CAS Chengdu Institute of Biology | Zhang Y.,CAS Chengdu Institute of Biology
Shengtai Xuebao/ Acta Ecologica Sinica | Year: 2010

The global climate is predicted to become significantly warmer over the next century. This will affect ecosystem processes and functioning of natural ecosystems in many parts of the world. It is well known that responses of ecosystem to climate warming may be more sensitive and rapid in high latitude regions and high altitude regions. The subalpine zone in eastern Qinghai-Tibet Plateau is a sensitive area of climate change and ecological fragile zone and this region is predicted to experience much greater increase in surface temperatures in the future. Thus, it is an ideal region to study the response mechanism of terrestrial ecosystems to climate change. Previous studies have illustrated that warming directly influenced the plant phonology, physiological performance and species composition and increase growth and dry mass production. However, these studies have often focused on effects of short-term warming. Whereas short-term warming invariably increases the biomass of tree seedlings, it is far from clear whether elevated temperature will increase forest productivity in the long term. Thus, it is essential that the responses of subalpine tree species to long-term warming are studied. Abies faxoniana is a typical important plant species in the subalpine coniferous forest. Although A. faxoniana is an important forest tree species in China, its responses to elevated temperature remain largely unknown. Thus, our objective was to study the biomass responses of seedlings of A. faxoniana,to long-term experimental warming to provide insights into the growth of A. faxoniana seedlings under a future warmer climate. We use growth chamber to determine long-term effects of elevated temperature ((2.2±0.2)°C) on growth,biomass and its allocation in A. faxoniana seedlings for 65 months. These results showed that warming significantly increased growth in the basal diameter,height, whole-plant biomass, total leaf area of seedlings and specific leaf area (SLA) by 40. 02%, 33. 97%,24. 24%,35. 38% and 19. 02%, respectively. But there was no significant effect on leaf mass per area (LAM). Moreover, the leaf-weight ratio (LMR) of seedlings was inhibited by warming, implying that long-term warming had negatively affected on the foliage. The branch-and-stem weight ratio of seedlings (SMR) was significantly improved by 25. 84%, indicating that a larger biomass allocated to branch and stems under warming. However, warming had no significant effect on the root-weight ratio of seedlings (RMR), demonstrating that the ratio of biomass allocated to roots kept constant. The Root-and-leaf weight raito (RLR) was not affected by treatment while the Root-and-shoot weight ratio (RSR) was decreased by 6. 34%. In summary, the presents study suggests that long-term air warming enhanced seedling growth and altered biomass allocation pattern. Moreover, warming drive plant reallocate biomass from leaves to shoots, thus, reduced the photosynthesis resources. We concluded that A. faxoniana could adapt to climate change through biomass reallocation.


Wang S.,Wuhan University | Qi Z.,Wuhan University | Huang H.,Leshan Vocational and Technical College | Ding H.,Wuhan University
Analytical Letters | Year: 2012

Methotrexate is widely used for treatment of various neoplastic diseases. The present work details the voltammetric analysis of Methotrexate at a multi-walled carbon nanotube (MWNT) modified screen-printed electrode (SPE). The fabrication and evaluation of MWNT-derived screen-printed electrochemical sensors based on a MWNT ink are reported. The fabricated MWNT strips combine the attractive advantages of CNT materials and disposable screen printed electrodes. The anodic voltammetric behavior of methotrexate was studied using cyclic and square-wave voltammetric techniques in tris-HCl (pH = 7.5) solution. The oxidation of methotrexate was an irreversible adsorptive-driven process. The experimental conditions such as carbon ink, MWNT, pH, the concentration, and nature of buffer were investigated to optimize the determination of methotrexate. Under optimum conditions, the square-wave voltammetric peak currents were in a linear relationship to methotrexate concentrations in the range of 5.0 × 10-7M-1.0 × 10-4 M with a detection limit of 1.0 × 10-7 M. The MWNT/SPE showed good stability, selectivity, and was successfully used to quantify methotrexate in pharmaceutical formulations. © 2012 Copyright Taylor and Francis Group, LLC.


Ye C.A.,Leshan Vocational and Technical College | Zhang X.F.,Chengdu Land Reserve Center
Advanced Materials Research | Year: 2014

Polycrystalline silicon-photovoltaic industry belongs to high-and-new technology industry, but it produces massive by-products (silicon tetrachloride and so on), even partial chloro-silicane and hydrogen chloride exude into the exhaust in its production process. As a consequence, it not only increases the exhaust processing cost in the polycrystalline silicon-photovoltaic industry, but also increases pollutant discharge of the enterprise. At present, Chinese polycrystalline silicon-photovoltaic enterprises cannot solve technical difficult problems in large-scale production due to lack of coordination of chemical industry. Moreover, polycrystalline silicon has high request of purity that needs quite advanced technology to achieve. This article introduces influences upon production cost and energy consumption with the use of improved Siemens method, and proposes that polytrophic-photovoltaic industry needs to be systematized, normalized and standardized for its healthy development. © (2014) Trans Tech Publications, Switzerland.


Zhang Z.,University of Sichuan | Yi X.,Leshan Vocational and Technical College | Peng H.,Xihua University
Bio-Medical Materials and Engineering | Year: 2014

This paper proposes a tissue membrane system-based framework to deal with the optimal image fusion problem. A spatial domain fusion algorithm is given, and a tissue membrane system of multiple cells is used as its computing framework. Based on the multicellular structure and inherent communication mechanism of the tissue membrane system, an improved velocity-position model is developed. The performance of the fusion framework is studied with comparison of several traditional fusion methods as well as genetic algorithm (GA)-based and differential evolution (DE)-based spatial domain fusion methods. Experimental results show that the proposed fusion framework is superior or comparable to the other methods and can be efficiently used for image fusion. © 2014 - IOS Press and the authors.


Chen A.Q.,Leshan Vocational and Technical College | Shao Q.Y.,South China Normal University
Science China: Physics, Mechanics and Astronomy | Year: 2011

The P + α-Si /N + polycrystalline solar cell is molded using the AMPS-1D device simulator to explore the new high efficiency thin film poly-silicon solar cell. In order to analyze the characteristics of this device and the thickness of N + poly-silicon, we consider the impurity concentration in the N + poly-silicon layer and the work function of transparent conductive oxide (TCO) in front contact in the calculation. The thickness of N + poly-silicon has little impact on the device when the thickness varies from 20 μm to 300 μm. The effects of impurity concentration in polycrystalline are analyzed. The conclusion is drawn that the open-circuit voltage (V oc) of P + α-Si /N + polycrystalline solar cell is very high, reaching 752 mV, and the conversion efficiency reaches 9.44%. Therefore, based on the above optimum parameters the study on the device formed by P + α-Si/N + poly-silicon is significant in exploring the high efficiency poly-silicon solar cell. © Science China Press and Springer-Verlag Berlin Heidelberg 2011.


Zhao Y.L.,Leshan Vocational and Technical College
Applied Mechanics and Materials | Year: 2013

The Internet of Things is currently the most popular field of communication and information research directions. Their application in the amount of information involved, are extremely large amount of data. How to ensure the transmission efficiency of business information under the premise of improving networking applications data security to protect the user's privacy data will be particularly important. Paper uses a custom data packet encapsulation mechanism, reducing the overhead of data resources; another based on their cross-platform communication features, combined with secure encryption and decryption, signature and authentication algorithm, the establishment of a secure communication system of things model for the differentiation of things communications environment, providing a standard packet structure, namely smart business security IOT application Protocol intelligent Service Security Application Protocol(ISSAP. © (2013) Trans Tech Publications, Switzerland.


Wang X.E.,Leshan Vocational and Technical College | Chen Z.Y.,Leshan Vocational and Technical College
Advanced Materials Research | Year: 2014

Isolation Control System Based on MRF magneto-rheological dampers analyze the structure and mechanical properties for engine isolation, the establishment of magnetorheological damper damping force of the theoretical model to clarify the magnetic current variable damper structural parameters, the motion parameters change its relationship performance impact of electromagnetic fields on the magneto-rheological dampers for numerical calculations. Research magnetorheological engine mounts intelligent control, real-time damping force adjustment, so that the vibration of the engine is transmitted to support the most effective attenuation of the time. © (2014) Trans Tech Publications, Switzerland.


Zhao Y.L.,Leshan Vocational and Technical College
Applied Mechanics and Materials | Year: 2014

This paper first discusses the basic principles of binocular stereo vision inspection, followed by discussion of the three-dimensional mathematical model of binocular vision sensor measurements, non-contact measurement accuracy binocular stereo vision again spring geometric parameters were analyzed, and then double-structure stereo vision sensor configurations were analyzed for binocular stereo vision to do a simple discussion of the basis for discussion. © (2014) Trans Tech Publications, Switzerland.

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