Research on Testing System for Three-dimensional Distribution of Luminous Intensity of LED

In terms of asymmetrical three-dimensional distribution(ID) of luminous intensity(LI) of light-emitting-diode(LED),a testing system was conducted in this study. Design and principle of the testing system were introduced. 31 photometers were placed on a concentric circle,and all of them were used to gather LI data of LED at the same time. The data acquisition card(DAC) was used to gather multichannel data and controlled motor. Experimental results indicated that the testing system had achieved the goal of testing three-dimensional distribution of LI. And each parameter could meet the requirements of industrial production and measurement.

CONVOLUTION OF THE IMPACT THREE-DIMENSIONAL ELASTO-DYNAMICS AND DYNAMIC STRESS INTENSITY FACTOR FOR AN ELLIPTIC CRACK

This paper presents a formulation for three-dimensional elasto-dynamics with an elliptic crack based on the Laplace and Fourier transforms andthe convolution theorem. The dynamic stress intensity factor for the crack is deter-mined by solving a Fredholm integral equation of the first kind. The results of thispaper are very close to those given by the two-dimensional dual integral equationmethod.

A STUDY ON STRESS INTENSITY FACTORS AND SINGULAR STRESS FIELDS OF THREE-DIMENSIONAL INTERFACE CRACK

By using the finite-part integral concepts and limit technique,the hypersingular inte-grodifferential equations of three-dimensional(3D)planar interface crack were obtained;then thedominant-part analysis of 2D hypersingular integral was further used to investigate the stress fieldsnear the crack front theoretically,and the accurate formulae were obtained for the singular stress fieldsand the complex stress intensity factors.After that,a numerical method is proposed to solve the hyper-singular integrodifferential equations of 3D planar interface crack,and the problem of elliptical planarcrack is then considered to show the application of the method.The numerical results obtained are sat-isfactory.

Experimental investigation of the mixing efficiency via intensity of segregation along axial direction of a rotating bar reactor

As a significant index to evaluate the mixing efficiency,studying the concentration distribution is directly related to the intensity of segregation(I_(s)).In this work,the I_(s) of the mixture composed of NaCl solutionwater was investigated experimentally in a rotating bar reactor(RBR)by the conductivity method.The results showed that the mixing efficiency was improved along the axial direction from the bottom to the top in the RBR.The concentration distribution at the bottom section was more uneven,and I_(s) was higher compared with the top section,which decreased from 6.53×10^(-5)to 1.57×10^(-7).With the increase of rotational speed from 0 to 700 r·min^(-1),I_s at the bottom and top sections decreased from 4.27×10^(-3)to 7.10×10^(-5)and from 1.93×10^(-3)to 7.29×10^(-7),respectively.The increases flow rate of solution A,and the decreases of concentration of NaCl and flow rate of solution B gave rise to the reduction of I_(s),signifying an improved mixing efficiency.The results revealed that the conductivity method used in this paper has high efficiency and low cost to measure the I_(s),which indicates a promising prospect for estimating reactors'mixing performance.

Three-Dimensional Analytical Modeling of Axial-Flux Permanent Magnet Drivers

In this paper, the axial-flux permanent magnet driver is modeledand analyzed in a simple and novel way under three-dimensional cylindricalcoordinates. The inherent three-dimensional characteristics of the deviceare comprehensively considered, and the governing equations are solved bysimplifying the boundary conditions. The axial magnetization of the sectorshapedpermanent magnets is accurately described in an algebraic form bythe parameters, which makes the physical meaning more explicit than thepurely mathematical expression in general series forms. The parameters of theBessel function are determined simply and the magnetic field distribution ofpermanent magnets and the air-gap is solved. Furthermore, the field solutionsare completely analytical, which provides convenience and satisfactoryaccuracy for modeling a series of electromagnetic performance parameters,such as the axial electromagnetic force density, axial electromagnetic force,and electromagnetic torque. The correctness and accuracy of the analyticalmodels are fully verified by three-dimensional finite element simulations and a15 kW prototype and the results of calculations, simulations, and experimentsunder three methods are highly consistent. The influence of several designparameters on magnetic field distribution and performance is studied and discussed.The results indicate that the modeling method proposed in this papercan calculate the magnetic field distribution and performance accurately andrapidly, which affords an important reference for the design and optimizationof axial-flux permanent magnet drivers.

Distribution characteristics of intensity and phase vortices of speckle fields produced by N-pinhole random screens

We analyze the distribution properties of phase and phase vortices in a speckle field generated by N-pinhole random screens, and find that the phase vortex distributions show similarity and clustering in local regions. The phase patterns have a lot of sets composed of two phase vortices with opposite signs or four phase vortices which are positive and negative vortices alternately. Cases are also found where two adjacent phase vortices have the same topological charges. The density of phase vortices becomes larger with the increase of the radius of circumference and the number of pinholes on screen.Then, the relative positions of phase vortices can be adjusted by changing the radius of circumference and the number of pinholes.

A Method of Inversing the Peak Density of Atomic Oxygen Vertical Distribution in the MLT Region From the OI (557.7 nm)Night Airglow Intensity

In this paper, using the MSISE-90 model as the reference atmosphere, we discuss the feasibility and method of deducing the peak densities of the undisturbed atomic oxygen profiles in the MLT region (the mesosphere and lower thermosphere region) from OI (557.7 nm) night airglow intersities. The peak densities for different seasons, latitudes and longitudes are deduced from OI (557.7nm) airglow intensities through this expression. We analyze the features of inversion relative errors and discuss the influence of the variations in temperature on inversion errors. The results indicate that all inversion errors are less than 5% except for those at high altitudes in the summer hemisphere. And the impact of the variations in temperature on errors is not significant.

Assessment of the Relationship between ESR Signal Intensity and Grain Size Distribution in Shear Zones within the Atotsugawa Fault System, Central Japan

For the first time, a relationship between ESR signal intensity and grain size distribution (sieve technique) in shear zones within the Atotsugawa fault system have been investigated using fault core rocks. The grain size distributions were estimated using the sieve technique and microscopic observations. Stacks of sieves with openings that decrease consecutively in the order of 4.75 mm, 1.18 mm, 600 μm, 300 μm, 150 μm and 75 μm were chosen for this study. Grain size distributions analysis revealed that samples further from the slip plane have larger d50 (average gain size) (0.45 mm at a distance of 30 - 50 mm from the slip plane) while those close to the slip plane have smaller d50 values (0.19 mm at a distance of 0 - 10 mm from the slip plane). This is due to intensive crushing that is always associated with large displacement during fault activities. However, this pattern was not respected in all shear zones in that, larger d50 values were instead observed in samples close to the slip plane due to admixture of fault rocks from different fault activities. Results from ESR analysis revealed that the relatively finer samples close to the slip plane have low ESR signals intensity while those further away (coarser) have relatively higher signal intensity. This tendency however, is not consistence in some of the shear zones due to a complex network of anatomizing faults. The variation in grain size distribution within some of the shear zones implies that, a series of fault events have taken place in the past thus underscoring the need for further investigation of the possibility of reoccurrence of faults.

Controlling Three-Dimensional Electron-Electron Correlation via Elliptically Polarized Intense Laser Field

The three-dimensional electron-electron correlation in an elliptically polarized laser field is investigated based on a semiclassical model. Asymmetry parameter α of the correlated electron momentum distribution is used to quantitatively describe the electron-electron correlation. The dependence of α on ellipticity ε is totally different in three directions. For the z direction(major polarization direction), α first increases and reaches a maximum at ε = 0.275, then it decreases quickly. For the y direction in which the laser field is always absent, the ellipticity has a minor effect, and the asymmetry parameter fluctuates around α =-0.15. However, for the x direction(minor polarization direction), α increases monotonously with ellipticity though starts from the same value as in the y direction when ε = 0. The behavior of α in the x direction actually indicates a transformation from the Coulomb interaction dominated correlation to the laser field dominated correlation. Therefore, our work provides an efficient way to control the three-dimensional electron-electron correlation via an elliptically polarized intense laser field.

The Prognostic Value of Red Cell Distribution Width in Critically Ill Cerebral Infarction Patients:A Retrospective Cohort Study

Objective:Red blood cell distribution width(RDW)has been utilized as a prognostic indicator for mortality risk assessment in cardiovascular and cerebrovascular patients.Nevertheless,the prognostic significance of RDW in critically ill patients with cerebral infarction is yet to be investigated.The objective of this study is to examine the association between RDW and the risk of all-cause mortality in cerebral infarction patients admitted to the intensive care unit(ICU).Method:A retrospective cohort study was conducted using the Medical Information Mart for Intensive Care IV 2.2(MIMIC-IV)intensive care dataset for data analysis.The main results were the all-cause mortality rates at 3 and 12 months of follow-up.Cumulative curves were plotted using the Kaplan-Meier method,and Cox proportional hazards analysis was used to examine the relationship between RDW and mortality rates in critically ill cerebral infarction patients.Results:The findings indicate that RDW serves as a significant prognostic factor for mortality risk in critically ill stroke patients,specifically at the 3 and 12-month follow-up periods.The observed correlation between increasing RDW levels and higher mortality rates among cerebral infarction patients further supports the potential utility of RDW as a predictive indicator.Conclusion:RDW emerges as an independent predictor of mortality risk during the 3 and 12-month follow-up periods for critically ill patients with cerebral infarction.

COMPARATIVE ANALYSIS OF THE INTENSITY AND DISTRIBUTION OF HEAVY RAINS IN ZHEJIANG PROVINCE CAUSED BY TYPHOONS HAITANG AND MATSA

Study was carried out on two landfall typhoons Haitang and Matsa, which affected Zhejiang province seriously in 2005. Firstly, the similarity and difference between the two typhoon-induced heavy rains were compared and it was pointed out that both of them brought strong large-scale precipitation and the maximum centers of rainfall were located on the north side of the landfall site. Making landfall on Fujian, Haitang was weaker than Matsa in intensity but surpassed it in rainfall. Then with focus on intensity, moving speed, structure of typhoon, circulation and terrain, the two typhoon-related heavy rains were compared and analyzed. Results show that the asymmetrical distribution of rainfall was closely related to the structure of typhoons themselves, moisture transportation and mesoscale terrain. In contrast to the south side, the north side was hotter and wetter and water vapor was also more abundant. The phenomenon of more rainfall induced by Haitang was in connection with the following reasons. Invading cold air led to rainfall increases, weakened dynamic field and slower movement both benefited precipitation. For the last part, the cold characteristic of air mass over Zhejiang was also a favorable factor for the rain.

Improving continuous-variable quantum key distribution under local oscillator intensity attack using entanglement in the middle

A modified continuous-variable quantum key distribution(CVQKD) protocol is proposed by originating the entangled source from a malicious third party Eve in the middle instead of generating it from the trustworthy Alice or Bob. This method is able to enhance the efficiency of the CVQKD scheme attacked by local oscillator(LO) intensity attack in terms of the generated secret key rate in quantum communication. The other indication of the improvement is that the maximum transmission distance and the maximum loss tolerance can be increased significantly, especially for CVQKD schemes based on homodyne detection.

Impact of intensity variability of the Asian summer monsoon anticyclone on the chemical distribution in the upper troposphere and lower stratosphere

亚洲夏季风期,平流层-对流层物质交换过程能显著影响上对流层下平流层化学成分的浓度变化和空间分布.然而,亚洲夏季风反气旋强度的季节内变化对其内部和周围地区化学成分水平分布的影响尚不清楚.本文将亚洲夏季风反气旋划分为季节内强周期和弱周期,发现当亚洲夏季风反气旋更强时,100 hPa O_(3)低值区的面积更大,O_(3)浓度更低.但是这种影响主要体现在6月份,7,8月的O_(3)水平分布还受东南亚地区深对流的影响.这些结果表明亚洲夏季风反气旋强度和深对流的季节内变化可以显著影响亚洲夏季风期上对流层下平流层的化学分布.

Modifying the intensity distribution by assessing the reliability

This article presents an application of a procedure to modify the intensity distribution by assessing the reliability.There are two potential possibilities that may influence the intensity distribution:(1)For the interpolation error,we generate a measured grid across the calculation region.When the point to station spacing is\5 km,we consider the results precise;however,some points have less precision because these are farther from the corresponding stations.When the spacing is between5 and 50 km,we consider the results imprecise and define a reliability factor that correlates with the distance.(2)Some records may have errors that result from local site conditions,equipment problems,or some disturbance such as lightning stroke,which will lead to some grid points having an incorrect intensity.We regress the attenuation relation for sites with abnormal intensities and consider the results to be accurate when the standard deviation(STD)is\r and inaccurate when the STD is[2r.We then define a reliability factor to correlate with STD between r and 2r,such that the intensity distribution is in accord with both wave propagation theory and the investigation intensity.

THREE-DIMENSIONAL ELLIPTIC CRACK UNDER IMPACT LOADING

The dynamic stress intensity factor of a three-dimensional elliptic crack under impact loadingis determined with the finite element method.The computation results can take into account the influence oftime and the ratio of the wave speeds on the stress intensity factor.The present method is suitable not onlyfor three-dimensional dynamic crack,but also for three-dimensional dynamic contact.

Effects of dry-wet cycles on three-dimensional pore structure and permeability characteristics of granite residual soil using X-ray micro computed tomography

Due to seasonal climate alterations,the microstructure and permeability of granite residual soil are easily affected by multiple dry-wet cycles.The X-ray micro computed tomography(micro-CT)acted as a nondestructive tool for characterizing the microstructure of soil samples exposed to a range of damage levels induced by dry-wet cycles.Subsequently,the variations of pore distribution and permeability due to drywet cycling effects were revealed based on three-dimensional(3D)pore distribution analysis and seepage simulations.According to the results,granite residual soils could be separated into four different components,namely,pores,clay,quartz,and hematite,from micro-CT images.The reconstructed 3D pore models dynamically demonstrated the expanding and connecting patterns of pore structures during drywet cycles.The values of porosity and connectivity are positively correlated with the number of dry-wet cycles,which were expressed by exponential and linear functions,respectively.The pore volume probability distribution curves of granite residual soil coincide with the χ^(2)distribution curve,which verifies the effectiveness of the assumption of χ^(2)distribution probability.The pore volume distribution curves suggest that the pores in soils were divided into four types based on their volumes,i.e.micropores,mesopores,macropores,and cracks.From a quantitative and visual perspective,considerable small pores are gradually transformed into cracks with a large volume and a high connectivity.Under the action of dry-wet cycles,the number of seepage flow streamlines which contribute to water permeation in seepage simulation increases distinctly,as well as the permeability and hydraulic conductivity.The calculated hydraulic conductivity is comparable with measured ones with an acceptable error margin in general,verifying the accuracy of seepage simulations based on micro-CT results.

Species spatial distributions in a warm-temperate deciduous broad-leaved forest in China

Spatial distribution is fundamental for understanding species coexistence mechanisms in forest communities.Here we comprehensively explored fine-scale spatial patterns of tree species in a secondary warm-temperate deciduous broad-leaved forest community in north China.Aggregated distribution patterns were predominant.Species functional traits had no significant effects on their spatial patterns.The aggregation intensity decreased with increasing DBH and abundance.The multivariate linear stepwise regression showed that abundance and maximum DBH were correlated with the aggregation intensity.Our results partially confirm that species attributes(abundance,DBH)and habitat heterogeneity may primarily contribute to spatial patterns and species coexistence in this secondary forest.

Formation mechanism of tight sandstone gas in areas of low hydrocarbon generation intensity: A case study of the Upper Paleozoic in north Tianhuan depression in Ordos Basin, NW China

The Upper Paleozoic in the north part of Tianhuan depression in the Ordos Basin,NW China has lower hydrocarbon generation intensity and complex gas-water relationship,the main factors controlling the formation of tight sandstone gas and the distribution of tight sandstone gas in the low hydrocarbon generation intensity area are studied.Through two-dimensional physical simulation experiment of hydrocarbon accumulation,analysis of reservoir micro-pore-throat hydrocarbon system and dissection of typical gas reservoirs,the evaluation models of gas injection pressure,reservoir physical property,and gas generation threshold were established to determine the features of tight gas reservoirs in low hydrocarbon intensity area:(1)at the burial depth of less than 3 000 m,the hydrocarbon generation intensity ofis high enough to maintain effective charging;(2)tight sandstone in large scale occurrence is conducive to accumulation of tight gas;(3)differences in reservoir physical property control the distribution of gas pool,for the channel sandstone reservoirs,ones with better physical properties generally concentrate in the middle of sandstone zone and local structural highs;ones with poor physical properties have low gas content generally.Based on the dissection of the gas reservoir in the north Tianhuan depression,the formation of tight gas reservoirs in low hydrocarbon generating intensity area are characterized by"long term continuous charging under hydrocarbon generation pressure,gas accumulation in large scale tight sandstone,pool control by difference in reservoir physical property,and local sweet spot",and the tight gas pools are distributed in discontinuous"sheets"on the plane.This understanding has been proved by expanding exploration of tight sandstone gas in the north Tianhuan depression.

Structural Design and Optimization of Comb-type Electric Bicycle Three-dimensional Parking Garage

With the reduction of urban land, the three-dimensional garage is increasingly built with its advantages of saving land. But the current three-dimensional garage is built for the car. It is hardly stereo parking garage for electric bicycles. This paper designed a hollow tower electric bicycle stereo parking garage with fork comb structure, based on the analysis of the characteristics of electric bicycles and the characteristics of existing three-dimensional garages. A fixed comb is mounted on the garage frame. The movable comb is mounted on the middle lift mechanism of the garage. The access of the vehicle is achieved by the exchange of the comb. The key comb structure was modeled using SolidWorks software and the stress distribution of the structure was analyzed. It was optimized by MATLAB software. The result shows that this structure can improve access efficiency. The quality of the comb structure can be minimized under the constraints of strength requirements.