期刊文献+
共找到72篇文章
< 1 2 4 >
每页显示 20 50 100
非均衡失效成本条件下的统计过程调整技术研究 被引量:2
1
作者 褚崴 于晓义 孙树栋 《计算机集成制造系统》 EI CSCD 北大核心 2008年第6期1168-1174,1181,共8页
为解决统计过程调整问题,建立了统计过程调整问题模型,采用公差设计和参数设计中的非均衡失效成本作为过程调整的评价指标,构建了过程方差参数未知和已知条件下的过程参数估计贝叶斯模型,进而构建了相应的质量特性值的预测模型。根据非... 为解决统计过程调整问题,建立了统计过程调整问题模型,采用公差设计和参数设计中的非均衡失效成本作为过程调整的评价指标,构建了过程方差参数未知和已知条件下的过程参数估计贝叶斯模型,进而构建了相应的质量特性值的预测模型。根据非均衡失效成本函数和质量特性值的预测模型,确定了过程每一步的最优控制目标,并根据控制目标完成过程调整。最后,在非均衡失效成本条件下,通过与格鲁布斯基本准则调整方法和马尔可夫链蒙特卡罗调整方法的对比,验证了本文中调整方法的性能优势。 展开更多
关键词 统计过程调整 非均衡失效成本 贝叶斯模型 预测模型 态变数 逼近式搜索算法
下载PDF
Study on the Quantity Dynamic Changes of Heterobacteria and Vibrios in Larvae Industrialized Culture System 被引量:7
2
作者 马妍 李健 +2 位作者 王斌 王群 刘淇 《Agricultural Science & Technology》 CAS 2008年第2期116-121,共6页
[ Objective ] The dynamic change of heterobacteria and vibrios in larvae industrialized culture system was studied to provide scientific reference for healthy cultivation of shrimp. [ Method ] The heterobacteria, vibr... [ Objective ] The dynamic change of heterobacteria and vibrios in larvae industrialized culture system was studied to provide scientific reference for healthy cultivation of shrimp. [ Method ] The heterobacteria, vibrios and pathogenic vibrio parahaemolyticus were monitored in larvae industrialized culture system. [ Result] The heterobacteria, vibrios and pathogenic vibrio parahaemolyticus were the most in fertilized eggs of shrimp but the least in nauplius, then their number would increase with growth. During whole rearing period, both boterobacteria in larvae, vibrios in water would increase by one order of magnitude, while both vibrios in larvae and heterobacteria in water would increase by two orders of magnitude. There were many heterobacteria and vibrios but few vibrio parahaemolyticus in living bait. The correlation coefficients between larvae and heterobacteria and vibrios in water were 0. 704 and 0. 840 in culture system respectively, while the correlation among heterobacteria, vibrios in living bait and larvae, water were weak or negative. [ Conclusion ] There was a dynamic relation between water and larvae in rearing period, and restrictly control of culture condition would restrain the occurrence of disease caused by vibrio parahaemolyticus, besides that bacteria number in bait was not obviously correlated with bacteria nubmer in culture system. 展开更多
关键词 Chinese shrimp larvae Heterotrophic bacteria VIBRIO Vibrio parahaemolyticus Dynamic change
下载PDF
Dynamic recrystallization behavior of 7085 aluminum alloy during hot deformation 被引量:12
3
作者 李东锋 张端正 +4 位作者 刘胜胆 单朝军 张新明 王琴 韩素琦 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2016年第6期1491-1497,共7页
The dynamic recrystallization behavior of 7085 aluminum alloy during hot compression at various temperatures (573?723 K) and strain rates (0.01-10 s^-1) was studied by electron back scattered diffraction (EBSD... The dynamic recrystallization behavior of 7085 aluminum alloy during hot compression at various temperatures (573?723 K) and strain rates (0.01-10 s^-1) was studied by electron back scattered diffraction (EBSD), electro-probe microanalyzer (EPMA) and transmission electron microscopy (TEM). It is shown that dynamic recovery is the dominant softening mechanism at high Zener?Hollomon (Z) values, and dynamic recrystallization tends to appear at low Z values. Hot compression with ln Z=24.01 (723 K, 0.01 s?1) gives rise to the highest fraction of recrystallization of 10.2%. EBSD results show that the recrystallized grains are present near the original grain boundaries and exhibit similar orientation to the deformed grain. Strain-induced boundary migration is likely the mechanism for dynamic recrystallization. The low density of Al3Zr dispersoids near grain boundaries can make contribution to strain-induced boundary migration. 展开更多
关键词 aluminum alloy Zener-Hollomon parameter dynamic recrystallization strain-induced boundary migration Al3Zr dispersoids
下载PDF
Forced convection rheoforming process for preparation of 7075 aluminum alloy semisolid slurry and its numerical simulation 被引量:13
4
作者 周冰 康永林 +3 位作者 朱国明 郜俊震 祁明凡 张欢欢 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2014年第4期1109-1116,共8页
A self-developed forced convection rheoforming (FCR) machine for the preparation of light alloy semisolid slurry was introduced. The microstructure characteristics of 7075 aluminium alloy semisolid slurry at differe... A self-developed forced convection rheoforming (FCR) machine for the preparation of light alloy semisolid slurry was introduced. The microstructure characteristics of 7075 aluminium alloy semisolid slurry at different stirring speeds prepared by the FCR process were analyzed. The experimental results suggest that with the increase of the stirring speed, the mean grain size of the semisolid decreases and the shape factor as well as the number of primary grains increase. Meanwhile, the preparation process of semisolid slurry was numerically simulated. The flow characteristics of the melt in the device and the effect of the stirring speed on temperature field and solid fraction of the melt were investigated. The simulated results show that during the preparation process of semisolid slurry, there is a complex convection within the FCR device that obviously changes the temperature field distribution and solid fraction of the melt. When the convection intensity increases, the scope of the undercooling gradient of the melt is reduced and temperature distribution is improved. 展开更多
关键词 7075 aluminum alloy forced convection rheoforming (FCR) semisolid slurry PREPARATION numerical simulation
下载PDF
Microstructure and properties of electronic packaging box with high silicon aluminum-base alloy by semi-solid thixoforming 被引量:10
5
作者 贾琪瑾 刘俊友 +1 位作者 李艳霞 王文韶 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2013年第1期80-85,共6页
The electronic packaging box with high silicon aluminum-base alloy was prepared by semi-solid thixoforming technique.The flow characteristic of the Si phase was analyzed.The microstructures of different parts of the b... The electronic packaging box with high silicon aluminum-base alloy was prepared by semi-solid thixoforming technique.The flow characteristic of the Si phase was analyzed.The microstructures of different parts of the box were observed by optical microscopy and scanning electron microscopy,and the thermophysical and mechanical properties of the box were tested.The results show that there exists the segregation phenomenon between the primary Si phase and the liquid phase during thixoforming,the liquid phase flows from the box,and the primary Si phase accumulates at the bottom of the box.The volume fraction of primary Si phase decreases gradually from the bottom to the walls.Accordingly,the thermal conductivities of bottom center and walls are 107.6 and 131.5 W/(m·K),the coefficients of thermal expansion(CTE) are 7.9×10-6 and 10.6×10-6 K-1,respectively.The flexural strength increases slightly from 167 to 180 MPa.The microstructures and properties of the box show gradient distribution overall. 展开更多
关键词 high silicon aluminum-base alloy electronic packaging semi-solid thixoforming thermal conductivity coefficient of thermal expansion
下载PDF
THE BOUNDARY ELEMENT ANALYSIS PROGRAM FOR 3-D TRANSIENT DYNAMIC FIELD
6
作者 刘佳岭 王晖 《Transactions of Tianjin University》 EI CAS 1997年第2期52-57,共6页
The matrix expression for the 3 D transient dynamic boundary integral equation in Laplace transform space is obtained and the degenerative element method has been implemented to treat the kernel function over the sin... The matrix expression for the 3 D transient dynamic boundary integral equation in Laplace transform space is obtained and the degenerative element method has been implemented to treat the kernel function over the singular element. In the computer program BEMTDY the Koizumi′s numerical inversion method is used and three examples of the 3 D vibrated foundation under harmonic forces and the influence with both adjacent foundations are studied. 展开更多
关键词 boundary element transient dynamic Laplace transform Green function
下载PDF
Salt-Water Transport in Unsaturated Soils Under Crop Planting: Dynamics and Numerical Simulation 被引量:7
7
作者 XU Li-Gang YANG Jing-Song +1 位作者 ZHANG Qi LIU Guang-Ming 《Pedosphere》 SCIE CAS CSCD 2005年第5期634-640,共7页
A laboratory salt-water dynamics experiment using unsaturated soils in packed silt loam and clay soil columns withdifferent soil texture profiles and groundwater levels under crops were conducted to study the changes ... A laboratory salt-water dynamics experiment using unsaturated soils in packed silt loam and clay soil columns withdifferent soil texture profiles and groundwater levels under crops were conducted to study the changes of salt-waterdynamics induced by water uptake of crops and to propose the theoretical basis for the regulation and control of salt-water dynamics as well as to predict salinity levels. The HYDRUS 1D model was applied to simulate the one-dimensionalmovement of water and salt transport in the soil columns. The results showed that the salts mainly accumulated in theplow layer in the soil columns under crops. Soil water and salt both moved towards the plow layer due to soil waterabsorption by the crop root system. The salt contents in the column with lower groundwater were mostly greater thanthose with high groundwater. The water contents in the soil columns increased from top to the bottom due to plant rootwater uptake. The changes in groundwater level had little influence on water content of the root zone in the soil columnswith crop planting. Comparison between the simulated and the determined values showed that model simulation resultswere ideal, so it is practicable to do numerical simulation of soil salt and water transport by the HYDRUS 1D model.Furthermore, if the actual movement of salt and water in fields is to be described in detail, much work needs to be done.The most important thing is to refine the parameters and select precise boundary conditions. 展开更多
关键词 crop planting numerical simulation salt accumulation salt-water dynamics
下载PDF
Theoretical Study on Mechanism and Kinetics of Reaction of O(^3p) with Propane 被引量:1
8
作者 荆富强 曹剑炜 +3 位作者 刘小君 胡煜峰 马海涛 边文生 《Chinese Journal of Chemical Physics》 SCIE CAS CSCD 2016年第4期430-436,I0001,共8页
The reaction of C3H8+O(^3p)→C3HT+OH is investigated using ab initio calculation and dynamical methods. Electronic structure calculations for all stationary points are obtained using a dual-level strategy. The geo... The reaction of C3H8+O(^3p)→C3HT+OH is investigated using ab initio calculation and dynamical methods. Electronic structure calculations for all stationary points are obtained using a dual-level strategy. The geometry optimization is performed using the unrestricted second-order Moller-Plesset perturbation method and the single-point energy is computed us- ing the coupled-cluster singles and doubles augmented by a perturbative treatment of triple excitations method. Results indicate that the main reaction channel is C3Hs+O(^3p)→i- C3HT+OH. Based upon the ab initio data, thermal rate constants are calculated using the variational transition state theory method with the temperature ranging from 298 K to 1000 K. These calculated rate constants are in better agreement with experiments than those reported in previous theoretical studies, and the branching ratios of the reaction are also calculated in the present work. Furthermore, the isotope effects of the title reaction are calculated and discussed. The present work reveals the reaction mechanism of hydrogenabstraction from propane involving reaction channel competitions is helpful for the understanding of propane combustion. 展开更多
关键词 Reaction mechanism Thermal rate constant Variational transition state theory Isotope effect
下载PDF
Equilibrium morphology of gas–liquid Janus droplets: A numerical analysis of buoyancy effect 被引量:1
9
作者 Shaobin Zhang Helen Yan +2 位作者 Yuhao Geng Ke Wang Jianhong Xu 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2018年第10期2121-2126,共6页
In this article, a theoretical model for predicting the equilibrium morphology of gas–liquid Janus droplets was built. Based on this model, the effects of bubble radius and volume ratio on morphology change was syste... In this article, a theoretical model for predicting the equilibrium morphology of gas–liquid Janus droplets was built. Based on this model, the effects of bubble radius and volume ratio on morphology change was systematically studied. The increase of bubble radius causes the two parts(bubble and oil drop) in Janus droplets tend to merge while the impact of volume ratio is complicated. When volume ratio increases, these two parts firstly tend to merge, then gradually separate. The accuracy of this model was verified by experimental results. 展开更多
关键词 MICROFLUIDICS Gas–liquid–liquid emulsion Janus droplets
下载PDF
Numerical simulation of intelligent compaction for subgrade construction 被引量:9
10
作者 MA Yuan LUAN Ying-cheng +1 位作者 ZHANG Wei-guang ZHANG Yu-qing 《Journal of Central South University》 SCIE EI CAS CSCD 2020年第7期2173-2184,共12页
During the compaction of a road subgrade, the mechanical parameters of the soil mass change in real time, but current research assumes that these parameters remain unchanged. In order to address this discrepancy, this... During the compaction of a road subgrade, the mechanical parameters of the soil mass change in real time, but current research assumes that these parameters remain unchanged. In order to address this discrepancy, this paper establishes a relationship between the degree of compaction K and strain ε. The relationship between the compaction degree K and the shear strength of soil(cohesion c and frictional angle φ) was clearly established through indoor experiments. The subroutine UMAT in ABAQUS finite element numerical software was developed to realize an accurate calculation of the subgrade soil compaction quality. This value was compared and analyzed against the assumed compaction value of the model, thereby verifying the accuracy of the intelligent compaction calculation results for subgrade soil. On this basis, orthogonal tests of the influential factors(frequency, amplitude, and quality) for the degree of compaction and sensitivity analysis were carried out. Finally, the ‘acceleration intelligent compaction value’, which is based on the acceleration signal, is proposed for a compaction meter value that indicates poor accuracy. The research results can provide guidance and basis for further research into the accurate control of compaction quality for roadbeds and pavements. 展开更多
关键词 intelligent compaction numerical simulation dynamic change control indicators orthogonal experiment
下载PDF
Status and distribution changes of the endangered Green Peafowl (Pavo muticus) in China over the past three decades (1990s-2017) 被引量:14
11
作者 Dejun Kong Fei Wu +4 位作者 Pengfei Shan Jianyun Gao Dao Yan Weixiong Luo Xiaojun Yang 《Avian Research》 CSCD 2018年第2期102-110,共9页
Background: Understanding the changes in population dynamics, including demographics, distribution and threats is essential for species status assessing.The endangered Green Peafowl (Povo muticus) has experienced s... Background: Understanding the changes in population dynamics, including demographics, distribution and threats is essential for species status assessing.The endangered Green Peafowl (Povo muticus) has experienced sharp population declines and d stribution range diminishing both in China and Southeast Asia. Field population surveys have not been conducted in China since the 1990s, which hindered conservation planning and decision-making.Methods: With interview and line transects methods, we figured out the population and distribution changes of Green Peafowl across its historical ranges over the past three decades in China during 2014-2017.Results: The Green Peafowl once habituated in 54 counties in China. Nearly 60% of the distribution counties were lost in the past three decades, with the left 22 counties distributed in central, southern and western Yunnan, SW China. Population decrease detected in all distribution areas except for Shuangbai and Xinping county where more than 60% of the total population is located. Only about 30% of the former bird population were recorded with the same interviewing method as 20 years ago.Three birds, 1 carcass, 6 calls and 12 footprints were detected along the 865 km line transects, indicating extremely low encounter rate of Green Peafowl in field. Sharp decreases in flock sizes were also detected, from 8-20 birds per flock in the 1990s to 3-5 birds at present. Poaching and habitat conversion are two widespread and long-lasting threats, while poison tion affect regional population's survival. Large flocks of 18 ng caused mortality in the past and hydropower construc -27 birds were discovered in the field, which increases our confidence of population recovery of this endangered pheasant in China.Conclusions: Only interviewed bird number and counts based on line transects were presented in this study, without further population estimation due to limitation of the data sets. Although the actual population of this cryptic bird must be underestimated, dramatic population declines and distribution concentrations of the endangered Green Peafowl occurred over the past 30 years in China undoubtedly. 展开更多
关键词 Green Peafowl Population decline Range concentration Endangered species Southwestern China
下载PDF
Stress redistribution of simply supported reinforced concrete beams under fire conditions 被引量:2
12
作者 DING Fa-xing LI Zhe YU Zhi-wu 《Journal of Central South University》 SCIE EI CAS CSCD 2018年第9期2093-2106,共14页
This study presents experimental and numerical investigations of simply supported steel reinforced concrete(RC)beams under fire.The temperature field of cross sections,the vertical deflection at mid-span,and specifica... This study presents experimental and numerical investigations of simply supported steel reinforced concrete(RC)beams under fire.The temperature field of cross sections,the vertical deflection at mid-span,and specifically the axial expansion displacement at beam-ends were measured during the fire tests.A novel finite element(FE)model of a RC beam under fire was developed,in which the water loss in the heat transfer analysis and the concrete transient strain in the mechanical analysis were considered.Based on the validated FE model proposed in this study,parametric studies were conducted to investigate the effects of the beam type,the protective layer thickness,and the load ratio on the thermal and mechanical behavior of simply supported RC beams.It was found that greater fire resistance and fire performance of girder beams in comparison to secondary beams contributed to the non-structural reinforcements,which effectively compensated for the reduced tensile capacities of structural reinforcements because of the degradation of the material properties.In addition,the history of normal stress distributions of concrete under fire can be divided into three phases:expansion,stress redistribution and plateau phases. 展开更多
关键词 reinforced concrete beam transient strain fire condition parametric analysis stress redistribution
下载PDF
Pseudo-dynamic analysis of overturning stability of retaining wall 被引量:4
13
作者 王奎华 马少俊 吴文兵 《Journal of Central South University》 SCIE EI CAS 2011年第6期2085-2090,共6页
A new method was presented to determine the safety factor of wall stability against overturning based on pseudo-dynamic approach. In this time-dependent method, the actual dynamic effect with variation of time and pro... A new method was presented to determine the safety factor of wall stability against overturning based on pseudo-dynamic approach. In this time-dependent method, the actual dynamic effect with variation of time and propagation of shear and primary wave velocities through the backfills was considered. Planar failure surface was considered behind the retaining wall. The results were compared with those obtained from Mononobe-Okabe theory. It is found that there is a higher value of safety factor by the present dynamic analysis. The effects of wall inclination, wall friction angle, soil friction angle and horizontal and vertical seismic coefficients on the overturning stability of retaining wall were investigated. The parametric study shows that both horizontal and vertical seismic accelerations have decreasing effect on the overturning stability of retaining wall. 展开更多
关键词 seismic active force pseudo-dynamic method EARTHQUAKE stability against overturning retaining wall
下载PDF
Dynamic Change of Landscape Pattern at Jilin Province from 1980 to 2000 被引量:1
14
作者 LI Jianping GAO Feng ZHANG Bai 《Geo-Spatial Information Science》 2007年第2期128-132,共5页
By using remote sensing images from three periods (1980, 1995, 2000) and with the support of GIS and RS, the spatial information of landscape elements of Jilin Province from 1980 to 2000 was interpreted and extracted.... By using remote sensing images from three periods (1980, 1995, 2000) and with the support of GIS and RS, the spatial information of landscape elements of Jilin Province from 1980 to 2000 was interpreted and extracted. Using models of landscape indices such as diversity, fragmentation, and mean patch fractal dimension, dynamic spatio-temporal changes of landscape patterns of the province were analyzed. The results: ① cropland and forestland were the main landscape types, and forestland became a landscape matrix; ② in the study area, landscapes were distributed unevenly, and there was low heterogeneity, a simple ecosystem structure and a tendency of irrational landscape patterns. There were also simple spatial shapes of patches and strong self-similarities, and in terms of dynamic change analysis, patch shapes tended to be more simple; ③ from 1980 to 2000, holistic landscape fragmentation was low and changed slightly. As far as landscape elements were concerned, the fragmentation of grassland, water area, land for residential area and factory facilities was relatively low; land distribution for residential areas and factory facilities was dispersed; and cropland and forestland were most concentrated-an indication that the trend will continue. Comprehensive effects among human activity, local policy, regional climate and environmental change led to the results. 展开更多
关键词 Jilin Province dynamic change landscape index landscape pattern
下载PDF
Self-Adaptive Topic Model: A Solution to the Problem of "Rich Topics Get Richer" 被引量:1
15
作者 FANG Ying 《China Communications》 SCIE CSCD 2014年第12期35-43,共9页
The problem of "rich topics get richer"(RTGR) is popular to the topic models,which will bring the wrong topic distribution if the distributing process has not been intervened.In standard LDA(Latent Dirichlet... The problem of "rich topics get richer"(RTGR) is popular to the topic models,which will bring the wrong topic distribution if the distributing process has not been intervened.In standard LDA(Latent Dirichlet Allocation) model,each word in all the documents has the same statistical ability.In fact,the words have different impact towards different topics.Under the guidance of this thought,we extend ILDA(Infinite LDA) by considering the bias role of words to divide the topics.We propose a self-adaptive topic model to overcome the RTGR problem specifically.The model proposed in this paper is adapted to three questions:(1) the topic number is changeable with the collection of the documents,which is suitable for the dynamic data;(2) the words have discriminating attributes to topic distribution;(3) a selfadaptive method is used to realize the automatic re-sampling.To verify our model,we design a topic evolution analysis system which can realize the following functions:the topic classification in each cycle,the topic correlation in the adjacent cycles and the strength calculation of the sub topics in the order.The experiment both on NIPS corpus and our self-built news collections showed that the system could meet the given demand,the result was feasible. 展开更多
关键词 topic model infinite Latent Dirichlet Allocation Dirichlet process topic evolution
下载PDF
Influence of heat treatment conditions on bending characteristics of 6063 aluminum alloy sheets 被引量:6
16
作者 Zhi-wen LIU Luo-xing LI +3 位作者 Jie YI Shi-kang LI Zhen-hu WANG Guan WANG 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2017年第7期1498-1506,共9页
Bending deformation behaviors of solution treated(ST),natural aged(NA)and T6tempered6063aluminum alloy sheetswere studied by three-point bending tests.The changes of bending force,interior angle,bending radius and she... Bending deformation behaviors of solution treated(ST),natural aged(NA)and T6tempered6063aluminum alloy sheetswere studied by three-point bending tests.The changes of bending force,interior angle,bending radius and sheet thickness in thefillet region were analyzed by experimental measurements and numerical simulations.The results showed that the bendingcharacteristics were strongly dependent on the heat treatment conditions.The T6alloy sheets were bent more sharply and localplastic deformation occurred severely in the fillet region.However,the ST and NA alloy sheets exhibited relatively uniform bendingdeformation and large bending radius.The bending force of T6alloy was the highest,followed by the NA alloy and that of the STalloy was minimum.After unloading,as compared with the ST and NA alloys,the springback of T6alloys was markedly larger.Theaging time showed a positive sensitivity on the springback and non-uniform bending deformability.The bending characteristics areattributed to the combined effects of yield strength,yield ratio and coefficient of neutral layer. 展开更多
关键词 6063 aluminum alloy three-point bending heat treatment conditions bending characteristic yield ratio simulation
下载PDF
Parameter Variations of Identified Model for Static Deformation Analysis of Arch Dam
17
作者 Jiann-Shiun Lew 《Journal of Civil Engineering and Architecture》 2016年第8期894-900,共7页
The structural health monitoring of a dam is important for maintaining the safe operation and longevity of the dam system. The structural health of a large dam can be monitored from the measured static deformation. Th... The structural health monitoring of a dam is important for maintaining the safe operation and longevity of the dam system. The structural health of a large dam can be monitored from the measured static deformation. This paper presents an investigation of the parameter variations of the identified model of the measured long-term static deformation for the structural health monitoring of Fui-Tsui Dam, which is located in a very active seismic zone of Taiwan. The measured static deformation is characterized as a function of the measured physical parameters, including the effects of hydrostatic pressure and temperature variation. The identified parameters, associated with the effects of hydrostatic pressure and temperature variation, change with environmental factors, such as flooding, earthquake and foundation change. 展开更多
关键词 Static deformation large dam MODELING parameter variation structural health monitoring.
下载PDF
Study Hankel Transforms and Properties of Bessel Function via Entangled State Representation Transformation in Quantum Mechanics
18
作者 FAN Hong-Yi WANG Yong 《Communications in Theoretical Physics》 SCIE CAS CSCD 2006年第5期819-824,共6页
In Phys. Lett. A 313 (2003) 343 we have found that the self-recipràcal Hankel transformation (HT) is embodied in quantum mechanics by a transform between two entangled state representations of continuum varia... In Phys. Lett. A 313 (2003) 343 we have found that the self-recipràcal Hankel transformation (HT) is embodied in quantum mechanics by a transform between two entangled state representations of continuum variables. In this work we study Hankel transforms and properties of Bessel function via entangled state representations' transformation in quantum mechanics. 展开更多
关键词 entangled state representation Hankel transform Bessel function
下载PDF
Four-Parameter Scheme for Ground Level of Helium Atom
19
作者 HU Xian-Quan XU Jie +1 位作者 MA Yong ZHENG Rui-Lun 《Communications in Theoretical Physics》 SCIE CAS CSCD 2006年第5期906-910,共5页
In this paper,the ground state wave function of four parameters is developed and expression of the ground state level is derived for the helium atom when the radial Schrodinger equation of the helium atom is solved. T... In this paper,the ground state wave function of four parameters is developed and expression of the ground state level is derived for the helium atom when the radial Schrodinger equation of the helium atom is solved. The ground energy is respectively computed by the optimized aJgorithms of Matlab 7.0 and the Monte Carlo methods. Furthermore, the ground state wave function is obtained. Compared with the experiment value and the value with the variation calculus in reference, the results of this paper show that in the four-parameter scheme, not only the calculations become more simplified and precise, but also the radial wave function of the helium atom meets the space symmetry automatically in ground state. 展开更多
关键词 helium atom ground state level variation calculus wave function
下载PDF
Analysis of Morphological Processes in a Disturbed Gravel-Bed River (Piave River): Integration of LiDAR Data and Colour Bathymetry
20
作者 Fabio Delai Johnny Moretto Lorenzo Picco Emanuel Rigon Diego Ravazzolo Mario Aristide Lenzi 《Journal of Civil Engineering and Architecture》 2014年第5期639-648,共10页
The magnitude of river morphological changes are better analyzed through the use of quantitative approaches, wherein resolution accuracy and uncertainty assessment are treated as crucial key-factors. In this sense, th... The magnitude of river morphological changes are better analyzed through the use of quantitative approaches, wherein resolution accuracy and uncertainty assessment are treated as crucial key-factors. In this sense, the creation of precise DEMs (Digital Elevation Models) of rivers represents an affordable tool to analyze geomorphic variations and budgets, except for wetted areas, where reliable channel digitalization can normally be obtained only using expensive bathymetric surveys. The proposed work aims at improving channel surface models without having available bathymetric sensors, by deriving dry areas elevations from LiDAR data and water depth of wetted areas from aerial photos through a predictive depth-colour relationship. The methodology was applied to two different sub-reaches of the Piave River, a gravel-bed river which suffered severe flood events in 2010. Erosion and deposition patterns were identified through DEM differencing, showing a predominance of scour processes which can lead to channel instability situations. The bathymetric output was compared to other previously-derived models confirming the accuracy of the in-channel elevation estimates. Finally, a discussion on the role played by longitudinal protections during the studied flood events is proposed, focusing the attention on the incidence of two major bank erosions that removed significant volumes of stable areas. 展开更多
关键词 Colour bathymetry LiDAR data flood impacts fluvial erosion-deposition processes effect of river protections.
下载PDF
上一页 1 2 4 下一页 到第
使用帮助 返回顶部