快速群搜索优化算法(Quick Group Search Optimizer,QGSO)是一种新近提出的启发式算法,本文将该算法应用到一个稍大规模的144杆扩展benchmark桁架结构优化问题,通过设计一系列独立重复试验的方法研究了QGSO算法中4个重要参数的取值,获得...快速群搜索优化算法(Quick Group Search Optimizer,QGSO)是一种新近提出的启发式算法,本文将该算法应用到一个稍大规模的144杆扩展benchmark桁架结构优化问题,通过设计一系列独立重复试验的方法研究了QGSO算法中4个重要参数的取值,获得了QGSO算法适用于大规模桁架结构优化设计的参数值,并将采用了新的参数设置值的算法命名为改良的快速群搜索优化算法(Modified Quick Group Search Optimizer,MQGSO)。尔后将MQGSO算法应用到一个大规模桁架结构优化设计问题中。计算结果表明,MQGSO算法适合求解这类优化问题,取得了比文献中应用其他各种启发式算法求得的更好的优化结果。展开更多
Perovskite solar cells(PSCs) have emerged as one of the most promising candidates for photovoltaic applications. Low-cost, low-temperature solution processes including coating and printing techniques makes PSCs promis...Perovskite solar cells(PSCs) have emerged as one of the most promising candidates for photovoltaic applications. Low-cost, low-temperature solution processes including coating and printing techniques makes PSCs promising for the greatly potential commercialization due to the scalability and compatibility with large-scale, roll-to-roll manufacturing processes. In this review, we focus on the solution deposition of charge transport layers and perovskite absorption layer in both mesoporous and planar structural PSC devices. Furthermore, the most recent design strategies via solution deposition are presented as well, which have been explored to enlarge the active area, enhance the crystallization and passivate the defects, leading to the performance improvement of PSC devices.展开更多
In order to develop the core chip supporting binocular stereo displays for head mounted display （HMD） and glasses-TV, a very large scale integrated （VISI） design scheme is proposed by using a pipeline architecture...In order to develop the core chip supporting binocular stereo displays for head mounted display （HMD） and glasses-TV, a very large scale integrated （VISI） design scheme is proposed by using a pipeline architecture for 3D display processing chip （HMD100）. Some key techniques including stereo display processing and high precision video scaling based bicubic interpolation, and their hardware implementations which improve the image quality are presented. The proposed HMD100 chip is verified by the field-programmable gate array （FPGA）. As one of innovative and high integration SoC chips, HMD100 is designed by a digital and analog mixed circuit. It can support binocular stereo display, has better scaling effect and integration. Hence it is applicable in virtual reality （VR）, 3D games and other microdisplay domains.展开更多
A lithium-assisted approach has been developed for the exfoliation of pristine graphite, which allows the large-scale preparation of few-layer graphene nanosheets. The process involves an unexpected physical insertion...A lithium-assisted approach has been developed for the exfoliation of pristine graphite, which allows the large-scale preparation of few-layer graphene nanosheets. The process involves an unexpected physical insertion and exfoliafion, and the graphene nanosheets prepared by this method reveal undisturbed sp2-hybridized structures. A possible two-step mechanism, which involves the negative charge being trapped around the edges of the graphite layers and a subsequent lithiation process, is proposed to explain the insertion of lithium inside the graphite interlayers. If necessary, the present exfoliation can be repeated and thinner （single or 2-3 layer） graphene can be achieved on a large scale. This simple process provides an efficient process for the exfoliation of pristine graphite, which might promote the future applications of graphene.展开更多
Interannual variation of summer precipitation in East China, and frequency of rainstorms during the monsoon season from 1961 to 2010, are analyzed in this study. It is found that the two variables show opposite trends...Interannual variation of summer precipitation in East China, and frequency of rainstorms during the monsoon season from 1961 to 2010, are analyzed in this study. It is found that the two variables show opposite trends on a decadal time scale: frequency of rainstorms increases significantly after the 1990 s, while summer precipitation in East China decreases during the same period. Analysis of the spatial distribution of summer rainstorm frequency from 1961 to 2010 indicates that it decreases from the southeast to the northwest at the east edge of the large-scale topography associated with the plateaus. Spatial distribution of rainstorms with daily rainfall greater than 50 mm is characterized by a "high in the southeast and low in the northwest" pattern, similar to the staircase distribution of the topography. However, the spatial distribution of variation in both summer precipitation and frequency of extreme rainstorms under global warming differs significantly from the three-step staircase topography. It is shown that moisture characteristics of summer precipitation and extreme rainstorms during the monsoon season in East China, including moisture transport pathways, moist flow pattern, and spatial structure of the merging area of moist flows, differ significantly. Areas of frequent rainstorms include the Yangtze River Valley and South China. Column-integrated moisture transport and its spatial structure could be summarized as a "merging" of three branches of intense moist flows from low and middle latitude oceans, and "convergence" of column-integrated moisture fluxes. The merging area for moist flow associated with rainstorms in the high frequency region is located slightly to the south of the monsoonal precipitation or non-rainstorm precipitation, with significantly strong moisture convergence. In addition, the summer moist flow pattern in East China has a great influence on the frequency of extreme rainstorms. Moisture flux vectors in the region of frequent rainstorms correspond to vortical flow pattern. A comparison of moisture flux vectors associated with non-rainstorms and rainstorms indicates that the moist vortex associated with rainstorms is smaller in size and located to the south of the precipitation maximum, while the moist vortex associated with non-rainstorms is larger and located to the north. It is shown that column-integrated moist transport vortices and the structure of moist flux convergence have significant impacts on the north-south oscillation of frequent rainstorm areas in East China, which is synchronized with the maximum vorticity of moisture transport and the minimum of convergence on the decadal time scale. Synthesis of moisture transport pathways and related circulation impacts leads to a conceptual model of moisture flow associated with rainstorms.展开更多
Based on the discrete wavelet transformation (DWT), we prese nt apixelized method of estimating the power spectra of galaxy samples. With lo cal properties of wavelet both in physical and wavenumber spaces, DWT power ...Based on the discrete wavelet transformation (DWT), we prese nt apixelized method of estimating the power spectra of galaxy samples. With lo cal properties of wavelet both in physical and wavenumber spaces, DWT power spec trum is equal to the corresponding band average of Fourier power spectrum. The D WT estimator is optimized in the sense that the spatial resolution is adaptive a utomatically to the perturbation wavelength to be studied. Under the assumption of ergodicity, the spatial average of local DWT fluctuation modes provides a fai r estimation of the ensemble average. We test DWT spectra of four typical cold da rk matter (CDM) structure formation models with numerical simulations. To consid er the infections of various observation effects to the DWT spectra, we introduc e irregular survey geometries, a given sampling rate, radial selection effects a nd redshift distortion effects into our mock samples. The numerical results show that, owing to its local properties, DWT spectrum is less affected by the sampl ing rate, survey geometry, and statistical ensemble fluctuations. With fast wave let decomposition algorithm, DWT can be used to analyze large survey samples, wh i ch is of direct significance in precise measurement of the cosmological paramete rs from the galaxy redshift surveys of next generation.展开更多
Mammals and other complex organisms can transcribe an abundance of long non-coding RNAs(lncRNAs)that fulfill a wide variety of regulatory roles in many biological processes.These roles,including as scaffolds and as gu...Mammals and other complex organisms can transcribe an abundance of long non-coding RNAs(lncRNAs)that fulfill a wide variety of regulatory roles in many biological processes.These roles,including as scaffolds and as guides for protein-coding genes,mainly depend on the structure and expression level of lncRNAs.In this review,we focus on the current methods for analyzing lncRNA structure and expression,which is basic but necessary information for in-depth,large-scale analysis of lncRNA functions.展开更多
文摘快速群搜索优化算法(Quick Group Search Optimizer,QGSO)是一种新近提出的启发式算法,本文将该算法应用到一个稍大规模的144杆扩展benchmark桁架结构优化问题,通过设计一系列独立重复试验的方法研究了QGSO算法中4个重要参数的取值,获得了QGSO算法适用于大规模桁架结构优化设计的参数值,并将采用了新的参数设置值的算法命名为改良的快速群搜索优化算法(Modified Quick Group Search Optimizer,MQGSO)。尔后将MQGSO算法应用到一个大规模桁架结构优化设计问题中。计算结果表明,MQGSO算法适合求解这类优化问题,取得了比文献中应用其他各种启发式算法求得的更好的优化结果。
基金Projects(51673214,51673218,61774170)supported by the National Natural Science Foundation of ChinaProject(2017YFA0206600)supported by the National Key Research and Development Program of China。
文摘Perovskite solar cells(PSCs) have emerged as one of the most promising candidates for photovoltaic applications. Low-cost, low-temperature solution processes including coating and printing techniques makes PSCs promising for the greatly potential commercialization due to the scalability and compatibility with large-scale, roll-to-roll manufacturing processes. In this review, we focus on the solution deposition of charge transport layers and perovskite absorption layer in both mesoporous and planar structural PSC devices. Furthermore, the most recent design strategies via solution deposition are presented as well, which have been explored to enlarge the active area, enhance the crystallization and passivate the defects, leading to the performance improvement of PSC devices.
文摘In order to develop the core chip supporting binocular stereo displays for head mounted display （HMD） and glasses-TV, a very large scale integrated （VISI） design scheme is proposed by using a pipeline architecture for 3D display processing chip （HMD100）. Some key techniques including stereo display processing and high precision video scaling based bicubic interpolation, and their hardware implementations which improve the image quality are presented. The proposed HMD100 chip is verified by the field-programmable gate array （FPGA）. As one of innovative and high integration SoC chips, HMD100 is designed by a digital and analog mixed circuit. It can support binocular stereo display, has better scaling effect and integration. Hence it is applicable in virtual reality （VR）, 3D games and other microdisplay domains.
基金This work was supported by the National Natural Science Foundation of China （No. 51222104） and the Fundamental Research Funds for the Central Universities.
文摘A lithium-assisted approach has been developed for the exfoliation of pristine graphite, which allows the large-scale preparation of few-layer graphene nanosheets. The process involves an unexpected physical insertion and exfoliafion, and the graphene nanosheets prepared by this method reveal undisturbed sp2-hybridized structures. A possible two-step mechanism, which involves the negative charge being trapped around the edges of the graphite layers and a subsequent lithiation process, is proposed to explain the insertion of lithium inside the graphite interlayers. If necessary, the present exfoliation can be repeated and thinner （single or 2-3 layer） graphene can be achieved on a large scale. This simple process provides an efficient process for the exfoliation of pristine graphite, which might promote the future applications of graphene.
基金supported by the National Natural Science Foundation of China (Grant No. 41130960)the National Science and Technology Pillar Program of China (Grant No. 2012BAK10B04)the National Department of Public Benefit Research Foundation of China (Grant No. GYHY201406001)
文摘Interannual variation of summer precipitation in East China, and frequency of rainstorms during the monsoon season from 1961 to 2010, are analyzed in this study. It is found that the two variables show opposite trends on a decadal time scale: frequency of rainstorms increases significantly after the 1990 s, while summer precipitation in East China decreases during the same period. Analysis of the spatial distribution of summer rainstorm frequency from 1961 to 2010 indicates that it decreases from the southeast to the northwest at the east edge of the large-scale topography associated with the plateaus. Spatial distribution of rainstorms with daily rainfall greater than 50 mm is characterized by a "high in the southeast and low in the northwest" pattern, similar to the staircase distribution of the topography. However, the spatial distribution of variation in both summer precipitation and frequency of extreme rainstorms under global warming differs significantly from the three-step staircase topography. It is shown that moisture characteristics of summer precipitation and extreme rainstorms during the monsoon season in East China, including moisture transport pathways, moist flow pattern, and spatial structure of the merging area of moist flows, differ significantly. Areas of frequent rainstorms include the Yangtze River Valley and South China. Column-integrated moisture transport and its spatial structure could be summarized as a "merging" of three branches of intense moist flows from low and middle latitude oceans, and "convergence" of column-integrated moisture fluxes. The merging area for moist flow associated with rainstorms in the high frequency region is located slightly to the south of the monsoonal precipitation or non-rainstorm precipitation, with significantly strong moisture convergence. In addition, the summer moist flow pattern in East China has a great influence on the frequency of extreme rainstorms. Moisture flux vectors in the region of frequent rainstorms correspond to vortical flow pattern. A comparison of moisture flux vectors associated with non-rainstorms and rainstorms indicates that the moist vortex associated with rainstorms is smaller in size and located to the south of the precipitation maximum, while the moist vortex associated with non-rainstorms is larger and located to the north. It is shown that column-integrated moist transport vortices and the structure of moist flux convergence have significant impacts on the north-south oscillation of frequent rainstorm areas in East China, which is synchronized with the maximum vorticity of moisture transport and the minimum of convergence on the decadal time scale. Synthesis of moisture transport pathways and related circulation impacts leads to a conceptual model of moisture flow associated with rainstorms.
基金Feng Longlong and Chu Yaoquan acknowledge the support from the National Natural Science Foundation of China.
文摘Based on the discrete wavelet transformation (DWT), we prese nt apixelized method of estimating the power spectra of galaxy samples. With lo cal properties of wavelet both in physical and wavenumber spaces, DWT power spec trum is equal to the corresponding band average of Fourier power spectrum. The D WT estimator is optimized in the sense that the spatial resolution is adaptive a utomatically to the perturbation wavelength to be studied. Under the assumption of ergodicity, the spatial average of local DWT fluctuation modes provides a fai r estimation of the ensemble average. We test DWT spectra of four typical cold da rk matter (CDM) structure formation models with numerical simulations. To consid er the infections of various observation effects to the DWT spectra, we introduc e irregular survey geometries, a given sampling rate, radial selection effects a nd redshift distortion effects into our mock samples. The numerical results show that, owing to its local properties, DWT spectrum is less affected by the sampl ing rate, survey geometry, and statistical ensemble fluctuations. With fast wave let decomposition algorithm, DWT can be used to analyze large survey samples, wh i ch is of direct significance in precise measurement of the cosmological paramete rs from the galaxy redshift surveys of next generation.
基金supported by the National High Technology Research and Development Program of China(2012AA020402)National Natural Science Foundation of China(11074084,30970558)
文摘Mammals and other complex organisms can transcribe an abundance of long non-coding RNAs(lncRNAs)that fulfill a wide variety of regulatory roles in many biological processes.These roles,including as scaffolds and as guides for protein-coding genes,mainly depend on the structure and expression level of lncRNAs.In this review,we focus on the current methods for analyzing lncRNA structure and expression,which is basic but necessary information for in-depth,large-scale analysis of lncRNA functions.
