在机器视觉感知系统中,从不完整的被遮挡的目标对象中鲁棒重建三维场景及其语义信息至关重要.目前常用方法一般将这两个功能分开处理,本文将二者结合,提出了一种基于深度图及分离池化技术的场景复原及语义分类网络,依据深度图中的RGB-D...在机器视觉感知系统中,从不完整的被遮挡的目标对象中鲁棒重建三维场景及其语义信息至关重要.目前常用方法一般将这两个功能分开处理,本文将二者结合,提出了一种基于深度图及分离池化技术的场景复原及语义分类网络,依据深度图中的RGB-D信息,完成对三维目标场景的重建与分类.首先,构建了一种CPU端到GPU端的深度卷积神经网络模型,将从传感器采样的深度图像作为输入,深度学习摄像机投影区域内的上下文目标场景信息,网络的输出为使用改进的截断式带符号距离函数(Truncated signed distance function, TSDF)编码后的体素级语义标注.然后,使用分离池化技术改进卷积神经网络的池化层粒度结构,设计带细粒度池化的语义分类损失函数,用于回馈网络的语义分类重定位.最后,为增强卷积神经网络的深度学习能力,构建了一种带有语义标注的三维目标场景数据集,以此加强本文所提网络的深度学习鲁棒性.实验结果表明,与目前较先进的网络模型对比,本文网络的重建规模扩大了2.1%,所提深度卷积网络对缺失场景的复原效果较好,同时保证了语义分类的精准度.展开更多
利用基于统计机器学习方法进行汉语语义角色标注(Semantic Role Labeling,SRL)存在人工抽取特征工作繁琐低效、模型难以捕捉长句上下文语义信息等问题.对此,提出BiLSTM-MaxPool-CRF融合模型进行汉语SRL,同时进行模型性能优化研究.首先,...利用基于统计机器学习方法进行汉语语义角色标注(Semantic Role Labeling,SRL)存在人工抽取特征工作繁琐低效、模型难以捕捉长句上下文语义信息等问题.对此,提出BiLSTM-MaxPool-CRF融合模型进行汉语SRL,同时进行模型性能优化研究.首先,在训练语料中融入词性、论元标记、短语句法等多层级语言学特征;然后,结合AvgPool技术对特征组进行采样选取;最后,通过多组实验结果表明,相比于未采样提取的多特征组,经过池化技术采样提取的多特征能够显著提高模型的性能.展开更多
In this paper, we apply the split-platform automated storage/retrieval systems (SP-AS/RSs) (Hu et al., 2005) to store containers in the yard to improve the yard performance and to increase the utilization of the yard ...In this paper, we apply the split-platform automated storage/retrieval systems (SP-AS/RSs) (Hu et al., 2005) to store containers in the yard to improve the yard performance and to increase the utilization of the yard space. The layout of an SP-AS/RS based yard is described in detail. To achieve an efficient operation, we present a novel yard space allocation policy called the ‘second-carrier-based allocation policy’, which can help to alleviate the out-of-sequence problem of containers and the congestion of vehicles at the AS/RS racks. Different allocation policies are compared by an integrated container terminal simulation system. The simulation results show that the second-carrier-based policy is very efficient and has the potential to offer high terminal performance.展开更多
On the basis of a general model of fuel cells, the entropy production rates of a fuel cell system under different conditions are derived by using theories of electrochemistry and thermodynamics. In order to analyze th...On the basis of a general model of fuel cells, the entropy production rates of a fuel cell system under different conditions are derived by using theories of electrochemistry and thermodynamics. In order to analyze the influence of the irreversible losses existing in an actual fuel cell, the equivalent circuit of the fuel cell is introduced, so that the irreversible factor of the fuel cell may be determined directly as a function of the internal, leak and load resistances. Moreover, the maximum power output and efficiency of the fuel cell are calculated, the optimal operation of the fuel cell is discussed, and the matching condition of the load resistance is determined.展开更多
Solid oxide fuel cells (SOFCs) offer a clean, pollution-free technology for the electrochemical conversion of chemical energy of hydrocarbon fuels into electricity. Many programs are being initiated in the United Stat...Solid oxide fuel cells (SOFCs) offer a clean, pollution-free technology for the electrochemical conversion of chemical energy of hydrocarbon fuels into electricity. Many programs are being initiated in the United States, Europe, Japan and so on. The funding for SOFC development worldwide has risen dramatically and this trend is expected to continue for at least the next decades. These development programs are also investigating wider applications of SOFCs in stationary, residential, transportation and military sectors. Finally, it is summarized the key materials and fabrication processes of SOFC in this paper.展开更多
This paper shows the development of solid oxide fuel cell (SOFC) technology at the Institute of Nuclear Energy Research. In the development, fabrication processes for planar anode-supported-cell (ASC) by conventio...This paper shows the development of solid oxide fuel cell (SOFC) technology at the Institute of Nuclear Energy Research. In the development, fabrication processes for planar anode-supported-cell (ASC) by conventional methods and metal-supported-cell (MSC) by atmospheric plasma spraying are well established. Procedures and techniques for stacking and cell/stack performance tests are continuously improved to enhance the quality and reliability. Innovative nano-structured catalysts, in which reduced Pt and CeOz particles dispersed onto the A120~ carriers can effectively prevent the migration and coalescence of the metal crystallites, are thermal stable and possess a conversion ratio higher than 95% for reforming of natural gas. A non-premixed after-burner/reformer is designed and fabricated, and it has passed the prerequisite functional tests. Layouts including stacks, components of BOP, power conditioning and control as well as gases and water supply, are designated for a 1-kW SOFC power system. In compliance with system requirements, operating modes, data acquisition, power conditioning, instrumentations, and control logics have been identified and settled. After successive system validation tests, two modules of 18-cell stacks are allocated into the SOFC system. Test results indicate a thermal self-sustaining system on natural gas is achieved with a power output of around 760 watts.展开更多
Rising fuel prices, increasing emission levels and impending environmental regulations made shipping industry to find an alternate for internal combustion engine in 21st century. Fuel cell is a sustainable, emerging t...Rising fuel prices, increasing emission levels and impending environmental regulations made shipping industry to find an alternate for internal combustion engine in 21st century. Fuel cell is a sustainable, emerging technology with negligible pollution. More significantly for a research ship, emission levels need to be substantially low to have quality measurements. A feasibility study is carried-out First time in the world, to drive an ice class multi-disciplinary ORV (Oceanography Research Vessel) Sagarnidbi, using hydrogen powered fuel cell. Sagamidhi is equipped with special equipments viz., Deep Sea winch, specially designed cranes for Launching and retrieval of ROV (Remotely Operable Vehicle), DSMC (Deep Sea Mining Crawler), Tsunami systems, manned/unmanned submersible and ACS (Autonomous Coring System) and other facilities that support research in Indian, International and Antarctic waters. Beside this, the propulsion system along with DP (Dynamic Positioning), centralized air conditioning and special equipments require enormous electrical power. The combustion of diesel oil in an engine, that coupled with an alternator generates electrical power required, along with NOx (Nitrous Oxides), SOx (Sulphur Oxides) and PM (Particulate Matter) emissions. Shipping industry is the fourth largest contributor to air pollution and carbon emissions, particularly in coastal areas, and the growth rate makes the problem even more critical. Stringent international air pollution regulation and increasing fuel price paves the way for an alternative "green emission technology". Various fuel cells were analyzed with different combination of fuel, electrolyte and electrodes. From the analysis, it has been found that SOFC (Solid Oxide Fuel Cell) is most suitable for the present scenario. A fuel cell designed with hydrogen as fuel, zirconium oxides stabilized with yttrium oxide as electrolyte and zirconium electrodes is used for 1.5 MW power output and 0.5 MW through regenerator. Volume required for storage of hydrogen is in line with volume of fuel and a high standard safety measures were taken using sensors. The present system saves 3000 MT/annum of diesel oil costing 3,000,000 USD approximately.展开更多
With increasing heat fluxes caused by electronic components, dimples have attracted wide attention by researchers and have been applied to microchannel heat sink in modem advanced cooling technologies. In this work, t...With increasing heat fluxes caused by electronic components, dimples have attracted wide attention by researchers and have been applied to microchannel heat sink in modem advanced cooling technologies. In this work, the combination of dimples, impinging jets and microchannel heat sink was proposed to improve the heat transfer performance on a cooling surface with a constant heat flux 500 W/cm2. A mathematical model was ad- vanced for numerically analyzing the fluid flow and heat transfer characteristics of a microchannel heat sink with impinging jets and dimples (MHSIJD), and the velocity distribution, pressure drop, and thermal performance of MI-ISIJD were analyzed by varying the radii of dimples. The results showed that the combination of dimples and MHSIJ can achieve excellent heat transfer performance; for the MHSIJD model in this work, the maximum and average temperatures can be as low as 320 K and 305 K, respectively when mass flow rate is 30 g/s; when dimple radius is larger than 0.195 mm, both the heat transfer coefficient and the overall performance h/AP of MHSIJD are higher than those of MHSIJ.展开更多
A novel hybrid solar concentrating Photovoltaic/Thermal (CPV/T) system with beam splitting technique is presented. In this system, a beam splitter is used to separate the concentrated solar radiation into two parts: o...A novel hybrid solar concentrating Photovoltaic/Thermal (CPV/T) system with beam splitting technique is presented. In this system, a beam splitter is used to separate the concentrated solar radiation into two parts: one for the PV power generation and the other for thermal utility. The solar concentrator is a flat Fresnel-type concentrator with glass mirror reflectors. It can concentrate solar radiation onto solar cells with high uniformity, which is beneficial to improving the efficiency of solar cells. The thermal receiver is separated to the solar cells, and therefore, the thermal fluid can be heated to a relatively high temperature and does not affect the performance of solar cells. A dimensionless model was developed for the performance analysis of the concentrating system. The effects of the main parameters on the performance of the concentrator were analyzed. The beam splitter with coating materials Nb2O3 /SiO2 was designed by using the needle optimization technique, which can reflect about 71% of the undesired radiation for silicon cell(1.1m < 3m) to the thermal receiver for thermal utility. The performance of this CPV/T system was also theoretically analyzed.展开更多
The development of non-platinum(Pt) oxygen reduction reaction(ORR) catalysts with high activity and low cost is of great importance for large-scale commercialization of fuel cells. By means of density functional theor...The development of non-platinum(Pt) oxygen reduction reaction(ORR) catalysts with high activity and low cost is of great importance for large-scale commercialization of fuel cells. By means of density functional theory(DFT) computations, we theoretically identified that two-dimensional(2D) iron-porphyrin(Fe-Pp) sheet, in which the active Fe sites are distributed regularly and separately, is an appealing candidate. The pristine Fe-Pp sheet exhibits considerably high catalytic activity and four-electron selectivity for ORR. Especially, the adsorption of ORR intermediates on Fe-Pp sheet can be significantly weakened by the addition of axial cyanogen(CN) ligand, resulting in pronouncedly enhanced ORR activity. More interestingly, the d band center of CN attached Fe-Pp(Fe-Pp-CN) sheet can be further tuned by applying the external tensile or compressive strain, leading to an enhancement or suppression of ORR catalytic performance. In particular, under a small biaxial tensile strain of 2%, the ORR activity of Fe-Pp-CN sheet is even higher than that of Pt and reaches to the top of activity volcano. Our studies open new ways to design effective non-Pt ORR catalysts for fuel cell technology.展开更多
文摘在机器视觉感知系统中,从不完整的被遮挡的目标对象中鲁棒重建三维场景及其语义信息至关重要.目前常用方法一般将这两个功能分开处理,本文将二者结合,提出了一种基于深度图及分离池化技术的场景复原及语义分类网络,依据深度图中的RGB-D信息,完成对三维目标场景的重建与分类.首先,构建了一种CPU端到GPU端的深度卷积神经网络模型,将从传感器采样的深度图像作为输入,深度学习摄像机投影区域内的上下文目标场景信息,网络的输出为使用改进的截断式带符号距离函数(Truncated signed distance function, TSDF)编码后的体素级语义标注.然后,使用分离池化技术改进卷积神经网络的池化层粒度结构,设计带细粒度池化的语义分类损失函数,用于回馈网络的语义分类重定位.最后,为增强卷积神经网络的深度学习能力,构建了一种带有语义标注的三维目标场景数据集,以此加强本文所提网络的深度学习鲁棒性.实验结果表明,与目前较先进的网络模型对比,本文网络的重建规模扩大了2.1%,所提深度卷积网络对缺失场景的复原效果较好,同时保证了语义分类的精准度.
文摘利用基于统计机器学习方法进行汉语语义角色标注(Semantic Role Labeling,SRL)存在人工抽取特征工作繁琐低效、模型难以捕捉长句上下文语义信息等问题.对此,提出BiLSTM-MaxPool-CRF融合模型进行汉语SRL,同时进行模型性能优化研究.首先,在训练语料中融入词性、论元标记、短语句法等多层级语言学特征;然后,结合AvgPool技术对特征组进行采样选取;最后,通过多组实验结果表明,相比于未采样提取的多特征组,经过池化技术采样提取的多特征能够显著提高模型的性能.
基金the Agency for Science, Technology and Research, the Maritime and Port Authority,and Nanyang Technological University, Singapore
文摘In this paper, we apply the split-platform automated storage/retrieval systems (SP-AS/RSs) (Hu et al., 2005) to store containers in the yard to improve the yard performance and to increase the utilization of the yard space. The layout of an SP-AS/RS based yard is described in detail. To achieve an efficient operation, we present a novel yard space allocation policy called the ‘second-carrier-based allocation policy’, which can help to alleviate the out-of-sequence problem of containers and the congestion of vehicles at the AS/RS racks. Different allocation policies are compared by an integrated container terminal simulation system. The simulation results show that the second-carrier-based policy is very efficient and has the potential to offer high terminal performance.
文摘On the basis of a general model of fuel cells, the entropy production rates of a fuel cell system under different conditions are derived by using theories of electrochemistry and thermodynamics. In order to analyze the influence of the irreversible losses existing in an actual fuel cell, the equivalent circuit of the fuel cell is introduced, so that the irreversible factor of the fuel cell may be determined directly as a function of the internal, leak and load resistances. Moreover, the maximum power output and efficiency of the fuel cell are calculated, the optimal operation of the fuel cell is discussed, and the matching condition of the load resistance is determined.
基金support from the NSFC key projects (50730004, 50872150 )MOST projects(2009DFA6136)MOE projects(NCET-06-0203,20060290005)
文摘Solid oxide fuel cells (SOFCs) offer a clean, pollution-free technology for the electrochemical conversion of chemical energy of hydrocarbon fuels into electricity. Many programs are being initiated in the United States, Europe, Japan and so on. The funding for SOFC development worldwide has risen dramatically and this trend is expected to continue for at least the next decades. These development programs are also investigating wider applications of SOFCs in stationary, residential, transportation and military sectors. Finally, it is summarized the key materials and fabrication processes of SOFC in this paper.
文摘This paper shows the development of solid oxide fuel cell (SOFC) technology at the Institute of Nuclear Energy Research. In the development, fabrication processes for planar anode-supported-cell (ASC) by conventional methods and metal-supported-cell (MSC) by atmospheric plasma spraying are well established. Procedures and techniques for stacking and cell/stack performance tests are continuously improved to enhance the quality and reliability. Innovative nano-structured catalysts, in which reduced Pt and CeOz particles dispersed onto the A120~ carriers can effectively prevent the migration and coalescence of the metal crystallites, are thermal stable and possess a conversion ratio higher than 95% for reforming of natural gas. A non-premixed after-burner/reformer is designed and fabricated, and it has passed the prerequisite functional tests. Layouts including stacks, components of BOP, power conditioning and control as well as gases and water supply, are designated for a 1-kW SOFC power system. In compliance with system requirements, operating modes, data acquisition, power conditioning, instrumentations, and control logics have been identified and settled. After successive system validation tests, two modules of 18-cell stacks are allocated into the SOFC system. Test results indicate a thermal self-sustaining system on natural gas is achieved with a power output of around 760 watts.
文摘Rising fuel prices, increasing emission levels and impending environmental regulations made shipping industry to find an alternate for internal combustion engine in 21st century. Fuel cell is a sustainable, emerging technology with negligible pollution. More significantly for a research ship, emission levels need to be substantially low to have quality measurements. A feasibility study is carried-out First time in the world, to drive an ice class multi-disciplinary ORV (Oceanography Research Vessel) Sagarnidbi, using hydrogen powered fuel cell. Sagamidhi is equipped with special equipments viz., Deep Sea winch, specially designed cranes for Launching and retrieval of ROV (Remotely Operable Vehicle), DSMC (Deep Sea Mining Crawler), Tsunami systems, manned/unmanned submersible and ACS (Autonomous Coring System) and other facilities that support research in Indian, International and Antarctic waters. Beside this, the propulsion system along with DP (Dynamic Positioning), centralized air conditioning and special equipments require enormous electrical power. The combustion of diesel oil in an engine, that coupled with an alternator generates electrical power required, along with NOx (Nitrous Oxides), SOx (Sulphur Oxides) and PM (Particulate Matter) emissions. Shipping industry is the fourth largest contributor to air pollution and carbon emissions, particularly in coastal areas, and the growth rate makes the problem even more critical. Stringent international air pollution regulation and increasing fuel price paves the way for an alternative "green emission technology". Various fuel cells were analyzed with different combination of fuel, electrolyte and electrodes. From the analysis, it has been found that SOFC (Solid Oxide Fuel Cell) is most suitable for the present scenario. A fuel cell designed with hydrogen as fuel, zirconium oxides stabilized with yttrium oxide as electrolyte and zirconium electrodes is used for 1.5 MW power output and 0.5 MW through regenerator. Volume required for storage of hydrogen is in line with volume of fuel and a high standard safety measures were taken using sensors. The present system saves 3000 MT/annum of diesel oil costing 3,000,000 USD approximately.
基金financially supported by the National Natural Science Foundation of China(Grant No.51778511)the Hubei Provincial Natural Science Foundation of China(Grant No.2018CFA029)the Key Project of ESI Discipline Development of Wuhan University of Technology(WUT Grant No.2017001)
文摘With increasing heat fluxes caused by electronic components, dimples have attracted wide attention by researchers and have been applied to microchannel heat sink in modem advanced cooling technologies. In this work, the combination of dimples, impinging jets and microchannel heat sink was proposed to improve the heat transfer performance on a cooling surface with a constant heat flux 500 W/cm2. A mathematical model was ad- vanced for numerically analyzing the fluid flow and heat transfer characteristics of a microchannel heat sink with impinging jets and dimples (MHSIJD), and the velocity distribution, pressure drop, and thermal performance of MI-ISIJD were analyzed by varying the radii of dimples. The results showed that the combination of dimples and MHSIJ can achieve excellent heat transfer performance; for the MHSIJD model in this work, the maximum and average temperatures can be as low as 320 K and 305 K, respectively when mass flow rate is 30 g/s; when dimple radius is larger than 0.195 mm, both the heat transfer coefficient and the overall performance h/AP of MHSIJD are higher than those of MHSIJ.
基金supported by the National Basic Research Program of China ("973" Program), (Grantt No. 2010CB227305)the CAS Solar Energy Action Program (Grant No. CX2090130012)
文摘A novel hybrid solar concentrating Photovoltaic/Thermal (CPV/T) system with beam splitting technique is presented. In this system, a beam splitter is used to separate the concentrated solar radiation into two parts: one for the PV power generation and the other for thermal utility. The solar concentrator is a flat Fresnel-type concentrator with glass mirror reflectors. It can concentrate solar radiation onto solar cells with high uniformity, which is beneficial to improving the efficiency of solar cells. The thermal receiver is separated to the solar cells, and therefore, the thermal fluid can be heated to a relatively high temperature and does not affect the performance of solar cells. A dimensionless model was developed for the performance analysis of the concentrating system. The effects of the main parameters on the performance of the concentrator were analyzed. The beam splitter with coating materials Nb2O3 /SiO2 was designed by using the needle optimization technique, which can reflect about 71% of the undesired radiation for silicon cell(1.1m < 3m) to the thermal receiver for thermal utility. The performance of this CPV/T system was also theoretically analyzed.
基金supported by the National Natural Science Foundation of China (21403115 and 21522305)the Natural Science Foundation of Jiangsu Province (BK20150045)+1 种基金Innovation Project in Jiangsu Province (KYZZ16-0454)The priority academic program development of Jiangsu higher education institutions
文摘The development of non-platinum(Pt) oxygen reduction reaction(ORR) catalysts with high activity and low cost is of great importance for large-scale commercialization of fuel cells. By means of density functional theory(DFT) computations, we theoretically identified that two-dimensional(2D) iron-porphyrin(Fe-Pp) sheet, in which the active Fe sites are distributed regularly and separately, is an appealing candidate. The pristine Fe-Pp sheet exhibits considerably high catalytic activity and four-electron selectivity for ORR. Especially, the adsorption of ORR intermediates on Fe-Pp sheet can be significantly weakened by the addition of axial cyanogen(CN) ligand, resulting in pronouncedly enhanced ORR activity. More interestingly, the d band center of CN attached Fe-Pp(Fe-Pp-CN) sheet can be further tuned by applying the external tensile or compressive strain, leading to an enhancement or suppression of ORR catalytic performance. In particular, under a small biaxial tensile strain of 2%, the ORR activity of Fe-Pp-CN sheet is even higher than that of Pt and reaches to the top of activity volcano. Our studies open new ways to design effective non-Pt ORR catalysts for fuel cell technology.