Development of highly-efficient photovoltaic (PV) modules and expanding its application fields are significant for the further development of PV technologies and realization of innovative green energy infrastructure b...Development of highly-efficient photovoltaic (PV) modules and expanding its application fields are significant for the further development of PV technologies and realization of innovative green energy infrastructure based on PV. Especially, development of solar-powered vehicles as a new application is highly desired and very important for this end. This paper presents the impact of PV cell/module conversion efficiency on reduction in CO</span><sub><span style="font-family:Verdana;">2</span></sub><span style="font-family:Verdana;"> emission and increase in driving range of the electric based vehicles. Our studies show that the utilization of a highly-efficient (higher than 30%) PV module enables the solar-powered vehicle to drive 30 km/day without charging in the case of light weig</span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">h</span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">t cars with elec</span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">t</span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">ric mileage of 17</span></span></span><span><span><span style="font-family:""> </span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">km/kWh under solar irrad</span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">i</span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">a</span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">t</span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">ion of 3.7</span></span></span><span><span><span style="font-family:""> </span></span></span><span><span><span style="font-family:""><span style="font-family:Verdana;">kWh/m</span><sup><span style="font-family:Verdana;">2</span></sup><span style="font-family:Verdana;">/day, which means that the majority of the family cars in Japan can run only by the sunlight without supplying fossil fuels. Thus, it is essential to develop high-efficiency as well as low-cost solar cells and modules for automotive applications. The analytical results developed by the authors for conversion efficiency potential of various solar cells for choosing candidates of the PV modules for automotive applications are shown. Then we overview the conversion efficiency potential and recent progress of various Si tandem solar cells, such as III-V/Si, II-VI/Si, chalcopyrite/Si, and perovskite/Si tandem solar cells. The III-V/Si tandem solar cells are expected to have a high potential for various applications because of its high conversion efficiency of larger than 36% for dual-junction and 42% for triple-junction solar cells under 1-sun AM1.5 G illumination, lightweight and low-cost potentials. The analysis show</span></span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">s</span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;"> that III-V based multi-junction and Si based tandem solar cells are considered to be promising candidates for the automotive application. Finally, we report recent results for our 28.2% efficiency and Sharp’s 33% mechanically stacked InGaP/GaAs/Si triple-junction solar cell. In addition, new approaches which </span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">are</span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;"> suitable for automotive applications by using III-V triple-junction, and static low concentrator PV modules are also presented.展开更多
Retaining or improving periodontal ligament (PDL) function is crucial for restoring periodontal defects. The aim of this study was to evaluate the physiological effects of low-power laser irradiation (LPLI) on the...Retaining or improving periodontal ligament (PDL) function is crucial for restoring periodontal defects. The aim of this study was to evaluate the physiological effects of low-power laser irradiation (LPLI) on the proliferation and osteogenic differentiation of human PDL (hPDL) cells. Cultured hPDL cel Is were irradiated (660 nm) daily with doses of O, 1, 2 or 4 J .cm-2. Cell proliferation was evaluated by the 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide (MTT) assay, and the effect of LPLI on osteogenic differentiation was assessed by Alizarin Red S staining and alkaline phosphatase (ALP) activity. Additionally, osteogenic marker gene expression was confirmed by real-time reverse transcription-polymerase chain reaction (RT-PCR). Our data showed that LPLI at a dose of 2 J.cm-2 significantly promoted hPDL cell proliferation at days 3 and 5. In addition, LPLI at energy doses of 2 and 4 J.cm-2 showed potential osteogenic capacity, as it stimulated ALP activity, calcium deposition, and osteogenic gene expression. We also showed that cyclic adenosine monophosphate (cAMP) is a critical regulator of the LPLI-mediated effects on hPDL cells. This study shows that LPLI can promote the proliferation and osteogenic differentiation of hPDL cells. These results suggest the potential use of LPLI in clinical applications for periodontal tissue regeneration.展开更多
Power electronics is an enabling technology for the development of environmental friendly fuel cell vehicles, and to implement the various vehicle electrical architectures to obtain the best performance. In this paper...Power electronics is an enabling technology for the development of environmental friendly fuel cell vehicles, and to implement the various vehicle electrical architectures to obtain the best performance. In this paper, power conversion strategies for propulsion and auxiliary power unit applications are described. The power electronics strategies for the successful development of the fuel cell vehicles are presented. The fuel cell systems for propulsion and for auxiliary power unit applications are also discussed.展开更多
BACKGROUND: Previous studies have demonstrated that low-power laser (LPL) irradiation can promote the regeneration of peripheral nerves and central nerves, as well as influence cellular proliferation. Therefore, it...BACKGROUND: Previous studies have demonstrated that low-power laser (LPL) irradiation can promote the regeneration of peripheral nerves and central nerves, as well as influence cellular proliferation. Therefore, it is thought to be a potential treatment for spinal cord injury. OBJECTIVE: Utilizing histological observations and behavioral evaluations, the aim of this study was to investigate the influence of transplanted olfactory ensheathing cells (OECs), irradiated by LPL, on functional repair of rats following transversal spinal cord injury. DESIGN, TIME AND SETTING: A randomized, controlled, animal experiment was performed at the animal experimental center in the First Affiliated Hospital of Xinjiang Medical University between January 2007 and February 2008. MATERIALS: A total of 52 Sprague Dawley rats were included in this experiment. Twelve rats were used to harvest OECs, some of which were irradiated by LPL on days 3, 5, and 7 in culture. The remaining 40 rats were used to establish T12 complete spinal cord transection injury. DMEM/F12 medium was purchased from Sigma, USA, Fluorogold was provided by Chemicon, USA, and the LY/JG650-D500-16 low-power laser was produced by Xi'an Lingyue Electromechanical Science And Technology Co., Ltd., China. METHODS: The successful rat models were randomly divided into three groups: OEC transplantation, LPL-irradiated OEC transplantation, and control. These animals were microinjected with OEC suspension, LPL-irradiated OEC suspension, and DMEM/F12 medium (10μL) respectively 4 weeks after spinal cord was completely transected at the T12 level. MAIN OUTCOME MEASURES: Spinal cord injury was observed using hematoxylin-eosin staining Expression of nerve growth factor receptor p75 and glial fibrillary acidic protein were determined using immunohistochemical staining. Regeneration of spinal nerve fibers in rats was assayed by Fluorogold retrograde labeling method. Basso, Beattie and Bresnahan (BBB) scores were used to evaluate motor functions of rat lower limbs. RESULTS: Structural disturbances were observed following spinal cord injury in each group, and a large amount of scar tissue covered the broken ends, accompanied by porosis and inflammatory cell infiltration. Following OEC transplantation, the distal end connected to the proximal end. nerve growth factor receptor p75 and glial fibrillary acidic protein immunohistochemistry revealed positive OECs in the cephalad and caudal area of rats that received LPL-irradiated OEC transplantation. In the OECs group, only glial fibrillary acidic protein staining was observed. No staining was found in the control group. Neural fibers labeled with Fluorogold extended across the lesion area and into the cephalad and caudal area in the OECs and LPL-irradiated OECs groups, but were not present in the control group. BBB scores revealed statistically significant differences among the three groups (P 〈 0.05): OECs irradiated by LPL group 〉 OECs group 〉 control group. CONCLUSION: Transplantation of OECs and LPL-irradiated OECs promoted functional repair in the injured spinal cord of rats, although LPL-irradiated OECs resulted in greater beneficial effects.展开更多
Pulp and papermaking industries generate high volumes of carbohydrate-rich effluents. Microbial fuel cell(MFC) technology is based on organic materials' consumption and efficient power production. Using a classica...Pulp and papermaking industries generate high volumes of carbohydrate-rich effluents. Microbial fuel cell(MFC) technology is based on organic materials' consumption and efficient power production. Using a classical two-chamber lab-scale MFC design with an external resistance of2000 W, we investigated the effects of anode chamber biofilm adaptation(ACBA) and cathode chamber redox solutions(CCRS) on the operation efficiency of MFC when treating wastewater. In ACBA studies, biofilm growth activation showed an increase in the power density to 20.48, 35.18, and36.98 mW/m^2 when the acetate feeding concentrations were 3, 6, and 12 g/L,respectively. Improvement by biofilm adhesion on granular activated carbon(GAC) was examined by scanning electron microscopy(SEM). The obtained power density increased to 25.47, 33.42, and 40.39 mW/m^2 when the GAC particles concentrations were 0, 50, and 100 g/L, respectively. The generated power densities were 51.26 and 40.39 mW/m^2 as well as the obtained voltages were 0.41 and 0.72 V when the electrode area increased from 16 to 64 cm^2,respectively. Using the MFC optimized parameters, CCRS studies carried out using five different cathodic redox solutions. The results revealed that the use of manganese dioxide dissolved in hydrochloric acid generated the maximum power density of 112.6 mW/m^2, current density of 0.094 A/m^2, and voltage of1.20 V with a successful organic removal efficiency of 86.0% after 264 h of operation.展开更多
Here we report a regulation about power conversion in fuel cells. This regulation is expressed as that total power produced by fuel cells is always proportional to the square of the potential difference between the \{...Here we report a regulation about power conversion in fuel cells. This regulation is expressed as that total power produced by fuel cells is always proportional to the square of the potential difference between the \{equilibrium\} potential and work potential. With this regulation we deduced fuel cell performance equation which can describe the potential vs.the current performance curves, namely, polarization curves of fuel cells with three power source parameters: equilibrium potential E_0; internal resistance R; and power conversion coefficient K. The concept of the power conversion coefficient is a new criterion to evaluate and compare the characteristics and capacity of different fuel cells. The calculated values obtained with this equation agree with practical performance of different types of fuel cells.展开更多
In this paper, we propose a novel uplink power control algorithm, SMST, for multiple-input multiple-output orthogonal frequency-division multiple access (MIMQ-OFDMA).We perform an extensive system-level simulation t...In this paper, we propose a novel uplink power control algorithm, SMST, for multiple-input multiple-output orthogonal frequency-division multiple access (MIMQ-OFDMA).We perform an extensive system-level simulation to compare different uplink power control algorithms, including the FPC adopted in 3GPP LTE and LTE-Advanced. Simulations show that SMST adopted in IEEE 802.16m outperforms other algorithms in terms of spectral efficiency, cell-edge performance, interference control, and trade-off control between sector-accumulated throughput and cell-edge user throughput. The SMST performance gain over FPC can be more than 40%展开更多
Fuel cell powered vehicles have been developed as another alternative to internal combustion engine powered vehicles for some applications including passenger cars, buses, trains, motorcycles, forklifts, electric whee...Fuel cell powered vehicles have been developed as another alternative to internal combustion engine powered vehicles for some applications including passenger cars, buses, trains, motorcycles, forklifts, electric wheelchairs, electric trolleybuses, medical carts, military engines, personal sports craft, mobility devices and other self propelled equipment. Up to now, many researches have focused on the development of the power module in the Fuel cell vehicles (FCVs) and the components of these systems such as membranes, bipolar plates, and electrodes. However, our work in this study focuses on operating the integrated fuel cell power module system efficiently for various operating conditions such as pressure, relative humidity and operating modes. In our validation we have utilized PEMFC single cell, with active area geometry 16 cm2 and of 120 cm2. Some results obtained in our study shown significant performance indicators for PEMFC stack (composed of 2 cells and 4 cells in a series) at different humidification levels.展开更多
Aim:To study the effect of high power microwave (HPM) radiation on the testicular germ cell apoptosis. Methods: One hundred and twenty-five Spraque-Dawley rats were randomly divided into two groups, the control group ...Aim:To study the effect of high power microwave (HPM) radiation on the testicular germ cell apoptosis. Methods: One hundred and twenty-five Spraque-Dawley rats were randomly divided into two groups, the control group and the experimental group and the latter was further divided into four subgroups: 10 mW/cm2 5 min, 10 mW/cm210 min, 20 mw/cm2 5 min and 20 mW/cm210 min. The experimental groups were radiated with S wave band of 10 mW/ cm2,20 mW/cm2 high power microwave for 5 or 10 min. Testicular samples were taken at 6 h, 24 h, 48 h, 72 h and 5 d after radiation. The testicular germ cell apoptosis was detected by in situ terminal deoxynucleotityl transferase mediated dUTP nick end labeling (TUNEL). Results: The number of apoptotic cells of the 6 h, 24 h and 48 h experimental groups after 10 and 20 mW/cm2 radiation for 5 min was significantly larger than that of the controls (P< 0.01), especially after 10 mW/cm2 radiation. The number of the 6 h group reached the peak (161.27±+5.90)/5 convoluted tubules. The changes in the other experimental groups had no significant difference compared with the controls (P>0.05). Conclusion: HPM increases the germ cell apoptosis of rat testis, which is related to the time of radiation and sample acquisition. In the condition of the present test, 5 minutes of HPM radiation may significantly enhance testicular germ cell apoptosis and damage, which in turn may influence the reproductive function of the rats.展开更多
A three-dimensional approach to the effect of magnetic field incidence angle on electrical power and conversion efficiency is performed on a front-illuminated polycrystalline silicon bifacial solar cell. A solution of...A three-dimensional approach to the effect of magnetic field incidence angle on electrical power and conversion efficiency is performed on a front-illuminated polycrystalline silicon bifacial solar cell. A solution of the continuity equation allowed us to present the equations of photocurrent density, photovoltage and electric power. The influence of the angle of incidence of the magnetic field on the photocurrent density, the photovoltage and the electric power has been studied. The curves of electrical power versus dynamic junction velocity were used to extract the values of maximum electrical power and dynamic junction velocity and to calculate those of conversion efficiency. From this study, it is found that the conversion efficiency values increase with the angle of incidence of the magnetic field.展开更多
Low power supply operation with leakage power reduction is the prime concern in modern nano-scale CMOS memory devices. In the present scenario, low leakage memory architecture becomes more challenging, as it has 30% o...Low power supply operation with leakage power reduction is the prime concern in modern nano-scale CMOS memory devices. In the present scenario, low leakage memory architecture becomes more challenging, as it has 30% of the total chip power consumption. Since, the SRAM cell is low in density and most of memory processing data remain stable during the data holding operation, the stored memory data are more affected by the leakage phenomena in the circuit while the device parameters are scaled down. In this survey, origins of leakage currents in a short-channel device and various leakage control techniques for ultra-low power SRAM design are discussed. A classification of these approaches made based on their key design and functions, such as biasing technique, power gating and multi-threshold techniques. Based on our survey, we summarize the merits and demerits and challenges of these techniques. This comprehensive study will be helpful to extend the further research for future implementations.展开更多
In this work, we study the method for determining the maximum of the minority carrier recombination velocity at the junction Sfmax, corresponding to the maximum power delivered by the photovoltaic generator. For this,...In this work, we study the method for determining the maximum of the minority carrier recombination velocity at the junction Sfmax, corresponding to the maximum power delivered by the photovoltaic generator. For this, we study the temperature influence on the behavior of the front white biased solar cell in steady state. By solving the continuity equation of excess minority carrier in the base, we have established the expressions of the photocurrent density, the recombination velocity on the back side of the base Sb, and the photovoltage. The photocurrent density and the photovoltage are plotted as a function of Sf, called, minority carrier recombination velocity at the junction surface, for different temperature values. The illuminated I-V characteristic curves of the solar cell are then derived. To better characterize the solar cell, we study the electrical power delivered by the base of the solar cell to the external charge circuit as either junction surface recombination velocity or photovoltage dependent. From the output power versus junction surface recombination velocity Sf, we have deduced an eigenvalue equation depending on junction recombination velocity. This equation allows to obtain the maximum junction recombination velocity Sfmax corresponding to the maximum power delivered by the photovoltaic generator, throughout simulink model. Finally, we deduce the conversion efficiency of the solar cell.展开更多
Multi-hop relay is a significant topic in the wireless communication and it is provisioned in the 802.16j standards.At present,the major research on multi-hop relay is focused on the capacity,coverage,coordination,thr...Multi-hop relay is a significant topic in the wireless communication and it is provisioned in the 802.16j standards.At present,the major research on multi-hop relay is focused on the capacity,coverage,coordination,throughput,etc.But in this paper,a new concept about power-effective was discussed.Then,two power-effective coverage extension methods using two sectorized cellular approaches were introduced,i.e.,the widebeam three sector cell(WBTC) and the narrow-beam three sector cell(NBTC).Under such topologies,the consumption of power and optimal numbers of base stations(BSs) and relay stations(RSs) with respect to various user traffic densities were investigated.Finally,it is found that the performance of WBTC is better than NBTC.展开更多
The aim of this study is to determinate the electrical parameters of a white biased silicon solar cell submitted to an irradiation energy of particles (protons, helium, electrons and heavy ions). A theoretical study o...The aim of this study is to determinate the electrical parameters of a white biased silicon solar cell submitted to an irradiation energy of particles (protons, helium, electrons and heavy ions). A theoretical study of the influence of irradiation energy on the photocurrent density, the photovoltage, the maximum power, as well as the maximum efficiency of the solar cell is presented through a resolution of the continuity equation relative to excess minority carrier. Then the expressions of the photocurrent density Jph, the photovoltage Vph, and the excess minority carrier recombination velocity at the back side Sb are established dependent of irradiation parameters ∅p, Kl respectively irradiation flux and intensity. In this work, we propose a method for determining the recombination velocity of the excess minority carrier at the junction Sfmax corresponding to the maximum power point delivered by the photovoltaic generator under the influence of the irradiation. It is then obtained by calculating the derivative of the power with respect to the excess minority carrier recombination velocity Sf at the junction emitter-base. A transcendental equation solution is deduced as eigenvalue, leading to the junction recombination velocity of excess minority carrier and also yields the solar cell maximum conversion efficiency.展开更多
文摘Development of highly-efficient photovoltaic (PV) modules and expanding its application fields are significant for the further development of PV technologies and realization of innovative green energy infrastructure based on PV. Especially, development of solar-powered vehicles as a new application is highly desired and very important for this end. This paper presents the impact of PV cell/module conversion efficiency on reduction in CO</span><sub><span style="font-family:Verdana;">2</span></sub><span style="font-family:Verdana;"> emission and increase in driving range of the electric based vehicles. Our studies show that the utilization of a highly-efficient (higher than 30%) PV module enables the solar-powered vehicle to drive 30 km/day without charging in the case of light weig</span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">h</span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">t cars with elec</span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">t</span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">ric mileage of 17</span></span></span><span><span><span style="font-family:""> </span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">km/kWh under solar irrad</span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">i</span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">a</span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">t</span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">ion of 3.7</span></span></span><span><span><span style="font-family:""> </span></span></span><span><span><span style="font-family:""><span style="font-family:Verdana;">kWh/m</span><sup><span style="font-family:Verdana;">2</span></sup><span style="font-family:Verdana;">/day, which means that the majority of the family cars in Japan can run only by the sunlight without supplying fossil fuels. Thus, it is essential to develop high-efficiency as well as low-cost solar cells and modules for automotive applications. The analytical results developed by the authors for conversion efficiency potential of various solar cells for choosing candidates of the PV modules for automotive applications are shown. Then we overview the conversion efficiency potential and recent progress of various Si tandem solar cells, such as III-V/Si, II-VI/Si, chalcopyrite/Si, and perovskite/Si tandem solar cells. The III-V/Si tandem solar cells are expected to have a high potential for various applications because of its high conversion efficiency of larger than 36% for dual-junction and 42% for triple-junction solar cells under 1-sun AM1.5 G illumination, lightweight and low-cost potentials. The analysis show</span></span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">s</span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;"> that III-V based multi-junction and Si based tandem solar cells are considered to be promising candidates for the automotive application. Finally, we report recent results for our 28.2% efficiency and Sharp’s 33% mechanically stacked InGaP/GaAs/Si triple-junction solar cell. In addition, new approaches which </span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">are</span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;"> suitable for automotive applications by using III-V triple-junction, and static low concentrator PV modules are also presented.
基金supported by grants from the Kaohsiung Medical University of Taiwan (KMU-Q099018 and KMU-Q098025)
文摘Retaining or improving periodontal ligament (PDL) function is crucial for restoring periodontal defects. The aim of this study was to evaluate the physiological effects of low-power laser irradiation (LPLI) on the proliferation and osteogenic differentiation of human PDL (hPDL) cells. Cultured hPDL cel Is were irradiated (660 nm) daily with doses of O, 1, 2 or 4 J .cm-2. Cell proliferation was evaluated by the 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide (MTT) assay, and the effect of LPLI on osteogenic differentiation was assessed by Alizarin Red S staining and alkaline phosphatase (ALP) activity. Additionally, osteogenic marker gene expression was confirmed by real-time reverse transcription-polymerase chain reaction (RT-PCR). Our data showed that LPLI at a dose of 2 J.cm-2 significantly promoted hPDL cell proliferation at days 3 and 5. In addition, LPLI at energy doses of 2 and 4 J.cm-2 showed potential osteogenic capacity, as it stimulated ALP activity, calcium deposition, and osteogenic gene expression. We also showed that cyclic adenosine monophosphate (cAMP) is a critical regulator of the LPLI-mediated effects on hPDL cells. This study shows that LPLI can promote the proliferation and osteogenic differentiation of hPDL cells. These results suggest the potential use of LPLI in clinical applications for periodontal tissue regeneration.
文摘Power electronics is an enabling technology for the development of environmental friendly fuel cell vehicles, and to implement the various vehicle electrical architectures to obtain the best performance. In this paper, power conversion strategies for propulsion and auxiliary power unit applications are described. The power electronics strategies for the successful development of the fuel cell vehicles are presented. The fuel cell systems for propulsion and for auxiliary power unit applications are also discussed.
基金Supported by:Scientific Research Program of the Higher Education Institution of Xinjiang,No. XJEDU2006133
文摘BACKGROUND: Previous studies have demonstrated that low-power laser (LPL) irradiation can promote the regeneration of peripheral nerves and central nerves, as well as influence cellular proliferation. Therefore, it is thought to be a potential treatment for spinal cord injury. OBJECTIVE: Utilizing histological observations and behavioral evaluations, the aim of this study was to investigate the influence of transplanted olfactory ensheathing cells (OECs), irradiated by LPL, on functional repair of rats following transversal spinal cord injury. DESIGN, TIME AND SETTING: A randomized, controlled, animal experiment was performed at the animal experimental center in the First Affiliated Hospital of Xinjiang Medical University between January 2007 and February 2008. MATERIALS: A total of 52 Sprague Dawley rats were included in this experiment. Twelve rats were used to harvest OECs, some of which were irradiated by LPL on days 3, 5, and 7 in culture. The remaining 40 rats were used to establish T12 complete spinal cord transection injury. DMEM/F12 medium was purchased from Sigma, USA, Fluorogold was provided by Chemicon, USA, and the LY/JG650-D500-16 low-power laser was produced by Xi'an Lingyue Electromechanical Science And Technology Co., Ltd., China. METHODS: The successful rat models were randomly divided into three groups: OEC transplantation, LPL-irradiated OEC transplantation, and control. These animals were microinjected with OEC suspension, LPL-irradiated OEC suspension, and DMEM/F12 medium (10μL) respectively 4 weeks after spinal cord was completely transected at the T12 level. MAIN OUTCOME MEASURES: Spinal cord injury was observed using hematoxylin-eosin staining Expression of nerve growth factor receptor p75 and glial fibrillary acidic protein were determined using immunohistochemical staining. Regeneration of spinal nerve fibers in rats was assayed by Fluorogold retrograde labeling method. Basso, Beattie and Bresnahan (BBB) scores were used to evaluate motor functions of rat lower limbs. RESULTS: Structural disturbances were observed following spinal cord injury in each group, and a large amount of scar tissue covered the broken ends, accompanied by porosis and inflammatory cell infiltration. Following OEC transplantation, the distal end connected to the proximal end. nerve growth factor receptor p75 and glial fibrillary acidic protein immunohistochemistry revealed positive OECs in the cephalad and caudal area of rats that received LPL-irradiated OEC transplantation. In the OECs group, only glial fibrillary acidic protein staining was observed. No staining was found in the control group. Neural fibers labeled with Fluorogold extended across the lesion area and into the cephalad and caudal area in the OECs and LPL-irradiated OECs groups, but were not present in the control group. BBB scores revealed statistically significant differences among the three groups (P 〈 0.05): OECs irradiated by LPL group 〉 OECs group 〉 control group. CONCLUSION: Transplantation of OECs and LPL-irradiated OECs promoted functional repair in the injured spinal cord of rats, although LPL-irradiated OECs resulted in greater beneficial effects.
基金funded by the China Science and Technology Exchange Center(Grant No.2016YFE0114700)
文摘Pulp and papermaking industries generate high volumes of carbohydrate-rich effluents. Microbial fuel cell(MFC) technology is based on organic materials' consumption and efficient power production. Using a classical two-chamber lab-scale MFC design with an external resistance of2000 W, we investigated the effects of anode chamber biofilm adaptation(ACBA) and cathode chamber redox solutions(CCRS) on the operation efficiency of MFC when treating wastewater. In ACBA studies, biofilm growth activation showed an increase in the power density to 20.48, 35.18, and36.98 mW/m^2 when the acetate feeding concentrations were 3, 6, and 12 g/L,respectively. Improvement by biofilm adhesion on granular activated carbon(GAC) was examined by scanning electron microscopy(SEM). The obtained power density increased to 25.47, 33.42, and 40.39 mW/m^2 when the GAC particles concentrations were 0, 50, and 100 g/L, respectively. The generated power densities were 51.26 and 40.39 mW/m^2 as well as the obtained voltages were 0.41 and 0.72 V when the electrode area increased from 16 to 64 cm^2,respectively. Using the MFC optimized parameters, CCRS studies carried out using five different cathodic redox solutions. The results revealed that the use of manganese dioxide dissolved in hydrochloric acid generated the maximum power density of 112.6 mW/m^2, current density of 0.094 A/m^2, and voltage of1.20 V with a successful organic removal efficiency of 86.0% after 264 h of operation.
基金Supported by EPSRC Funds(No.GR/ R5 0 4 17) and an EPSRC/ HEFCF J.I.F Award(No.JIF4 NESCEQ )
文摘Here we report a regulation about power conversion in fuel cells. This regulation is expressed as that total power produced by fuel cells is always proportional to the square of the potential difference between the \{equilibrium\} potential and work potential. With this regulation we deduced fuel cell performance equation which can describe the potential vs.the current performance curves, namely, polarization curves of fuel cells with three power source parameters: equilibrium potential E_0; internal resistance R; and power conversion coefficient K. The concept of the power conversion coefficient is a new criterion to evaluate and compare the characteristics and capacity of different fuel cells. The calculated values obtained with this equation agree with practical performance of different types of fuel cells.
文摘In this paper, we propose a novel uplink power control algorithm, SMST, for multiple-input multiple-output orthogonal frequency-division multiple access (MIMQ-OFDMA).We perform an extensive system-level simulation to compare different uplink power control algorithms, including the FPC adopted in 3GPP LTE and LTE-Advanced. Simulations show that SMST adopted in IEEE 802.16m outperforms other algorithms in terms of spectral efficiency, cell-edge performance, interference control, and trade-off control between sector-accumulated throughput and cell-edge user throughput. The SMST performance gain over FPC can be more than 40%
基金The Center for Renewable Energies Development (CDER)The General Directorate for Scientific Research and Tech- nological Development (DG-RSDT)+1 种基金The Na- tional Observatory of the Environment and the Durable Development (ONEDD)The Ministry of Town and Country Planning and the Environment
文摘Fuel cell powered vehicles have been developed as another alternative to internal combustion engine powered vehicles for some applications including passenger cars, buses, trains, motorcycles, forklifts, electric wheelchairs, electric trolleybuses, medical carts, military engines, personal sports craft, mobility devices and other self propelled equipment. Up to now, many researches have focused on the development of the power module in the Fuel cell vehicles (FCVs) and the components of these systems such as membranes, bipolar plates, and electrodes. However, our work in this study focuses on operating the integrated fuel cell power module system efficiently for various operating conditions such as pressure, relative humidity and operating modes. In our validation we have utilized PEMFC single cell, with active area geometry 16 cm2 and of 120 cm2. Some results obtained in our study shown significant performance indicators for PEMFC stack (composed of 2 cells and 4 cells in a series) at different humidification levels.
文摘Aim:To study the effect of high power microwave (HPM) radiation on the testicular germ cell apoptosis. Methods: One hundred and twenty-five Spraque-Dawley rats were randomly divided into two groups, the control group and the experimental group and the latter was further divided into four subgroups: 10 mW/cm2 5 min, 10 mW/cm210 min, 20 mw/cm2 5 min and 20 mW/cm210 min. The experimental groups were radiated with S wave band of 10 mW/ cm2,20 mW/cm2 high power microwave for 5 or 10 min. Testicular samples were taken at 6 h, 24 h, 48 h, 72 h and 5 d after radiation. The testicular germ cell apoptosis was detected by in situ terminal deoxynucleotityl transferase mediated dUTP nick end labeling (TUNEL). Results: The number of apoptotic cells of the 6 h, 24 h and 48 h experimental groups after 10 and 20 mW/cm2 radiation for 5 min was significantly larger than that of the controls (P< 0.01), especially after 10 mW/cm2 radiation. The number of the 6 h group reached the peak (161.27±+5.90)/5 convoluted tubules. The changes in the other experimental groups had no significant difference compared with the controls (P>0.05). Conclusion: HPM increases the germ cell apoptosis of rat testis, which is related to the time of radiation and sample acquisition. In the condition of the present test, 5 minutes of HPM radiation may significantly enhance testicular germ cell apoptosis and damage, which in turn may influence the reproductive function of the rats.
文摘A three-dimensional approach to the effect of magnetic field incidence angle on electrical power and conversion efficiency is performed on a front-illuminated polycrystalline silicon bifacial solar cell. A solution of the continuity equation allowed us to present the equations of photocurrent density, photovoltage and electric power. The influence of the angle of incidence of the magnetic field on the photocurrent density, the photovoltage and the electric power has been studied. The curves of electrical power versus dynamic junction velocity were used to extract the values of maximum electrical power and dynamic junction velocity and to calculate those of conversion efficiency. From this study, it is found that the conversion efficiency values increase with the angle of incidence of the magnetic field.
文摘Low power supply operation with leakage power reduction is the prime concern in modern nano-scale CMOS memory devices. In the present scenario, low leakage memory architecture becomes more challenging, as it has 30% of the total chip power consumption. Since, the SRAM cell is low in density and most of memory processing data remain stable during the data holding operation, the stored memory data are more affected by the leakage phenomena in the circuit while the device parameters are scaled down. In this survey, origins of leakage currents in a short-channel device and various leakage control techniques for ultra-low power SRAM design are discussed. A classification of these approaches made based on their key design and functions, such as biasing technique, power gating and multi-threshold techniques. Based on our survey, we summarize the merits and demerits and challenges of these techniques. This comprehensive study will be helpful to extend the further research for future implementations.
文摘In this work, we study the method for determining the maximum of the minority carrier recombination velocity at the junction Sfmax, corresponding to the maximum power delivered by the photovoltaic generator. For this, we study the temperature influence on the behavior of the front white biased solar cell in steady state. By solving the continuity equation of excess minority carrier in the base, we have established the expressions of the photocurrent density, the recombination velocity on the back side of the base Sb, and the photovoltage. The photocurrent density and the photovoltage are plotted as a function of Sf, called, minority carrier recombination velocity at the junction surface, for different temperature values. The illuminated I-V characteristic curves of the solar cell are then derived. To better characterize the solar cell, we study the electrical power delivered by the base of the solar cell to the external charge circuit as either junction surface recombination velocity or photovoltage dependent. From the output power versus junction surface recombination velocity Sf, we have deduced an eigenvalue equation depending on junction recombination velocity. This equation allows to obtain the maximum junction recombination velocity Sfmax corresponding to the maximum power delivered by the photovoltaic generator, throughout simulink model. Finally, we deduce the conversion efficiency of the solar cell.
文摘Multi-hop relay is a significant topic in the wireless communication and it is provisioned in the 802.16j standards.At present,the major research on multi-hop relay is focused on the capacity,coverage,coordination,throughput,etc.But in this paper,a new concept about power-effective was discussed.Then,two power-effective coverage extension methods using two sectorized cellular approaches were introduced,i.e.,the widebeam three sector cell(WBTC) and the narrow-beam three sector cell(NBTC).Under such topologies,the consumption of power and optimal numbers of base stations(BSs) and relay stations(RSs) with respect to various user traffic densities were investigated.Finally,it is found that the performance of WBTC is better than NBTC.
文摘The aim of this study is to determinate the electrical parameters of a white biased silicon solar cell submitted to an irradiation energy of particles (protons, helium, electrons and heavy ions). A theoretical study of the influence of irradiation energy on the photocurrent density, the photovoltage, the maximum power, as well as the maximum efficiency of the solar cell is presented through a resolution of the continuity equation relative to excess minority carrier. Then the expressions of the photocurrent density Jph, the photovoltage Vph, and the excess minority carrier recombination velocity at the back side Sb are established dependent of irradiation parameters ∅p, Kl respectively irradiation flux and intensity. In this work, we propose a method for determining the recombination velocity of the excess minority carrier at the junction Sfmax corresponding to the maximum power point delivered by the photovoltaic generator under the influence of the irradiation. It is then obtained by calculating the derivative of the power with respect to the excess minority carrier recombination velocity Sf at the junction emitter-base. A transcendental equation solution is deduced as eigenvalue, leading to the junction recombination velocity of excess minority carrier and also yields the solar cell maximum conversion efficiency.