Three-Dimensional and Cross-sectional Characteristics of Normal Grain Growth Based on Monte Carlo Simulation

An appropriate Monte Carlo method was developed to simulate the three-dimensional normal grain growth more completely. Comparative investigation on the three-dimensional and the cross-sectional characteristics of normal grain growth was done. It was found that the time exponent of grain growth determined from cross-section exhibits the same rule of increasing slowly with time and approaching the theoretical value n = 0.5 of steadygrain growth as the three-dimensional (3-D) system. From change of the number of grains per unit area with timemeasured in cross-section, the state of 3-D normal grain growth may be predicted. The gtain size distribution incross-section is different from that in 3-D system and can not express the evolution characteristic of the 3-D distribution. Furthermore, there exists statistical connection between the topological parameters in cross-section and thosein three-dimensions.

Validation of a Characteristics Dimensions for Transfers during Convective Drying of Sweet Potato Cubic, Cylindrical and Spherical Shapes

This present work solves the problem of initial shape influence on transfer during convective drying. A characteristic dimension is found for the cubic, cylindrical and spherical-shaped samples of the sweet potato. This characteristic dimension corresponds to the diameter D for the sphere, to the edge a for the cube and the diameter = height D = H for the cylinder. Unlike the sphere where this characteristic dimension is perfect, the cubic and cylindrical shapes have space factors which are, among other things, angles and borders. By fixing the same characteristic dimensions, we end up with overlapping curves, showing identical and uniform transfers.

Computational fluid dynamics simulations of respiratory airflow in human nasal cavity and its characteristic dimension study

To study the airflow distribution in human nasal cavity during respiration and the characteristic parameters of nasal structure, three-dimensional, anatomically accurate representations of 30 adult nasal cavity models were recons- tructed based on processed tomography images collected from normal people. The airflow fields in nasal cavities were simulated by fluid dynamics with finite element software ANSYS. The results showed that the difference of human nasal cavity structure led to different airflow distribution in the nasal cavities and variation of the main airstream passing through the common nasal meatus. The nasal resistance in the regions of nasal valve and nasal vestibule accounted for more than half of the overall resistance. The characteristic model of nasal cavity was extracted on the basis of characteristic points and dimensions deduced from the original models. It showed that either the geometric structure or the airflow field of the two kinds of models was similar. The characteristic dimensions were the characteristic parameters of nasal cavity that could properly represent the original model in model studies on nasal cavity.

Dynamic characteristics of the planetary gear train excited by time-varying meshing stiffness in the wind turbine

Wind power has attracted increasing attention as a renewable and clean energy. Gear fault frequently occurs under extreme environment and complex loads. The time-varying meshing stiffness is one of the main excitations. This study proposes a 5 degree-of-freedom torsional vibration model for the planetary gear system. The influence of some parameters(e.g., contact ratio and phase difference) is discussed under different conditions of a single teeth pair and double pairs of teeth. The impact load caused by the teeth face fault, ramped load induced by the complex wind conditions, and the harmonic excitation are investigated. The analysis of the time-varying meshing stiffness and the dynamic meshing force shows that the dynamic design under different loads can be made to avoid resonance, can provide the basis for the gear fault location of a wind turbine, and distinguish the fault characteristics from the vibration signals.

Time-variant reliability analysis of three-dimensional slopes based on Support Vector Machine method

In the reliability analysis of slope, the performance functions derived from the most available stability analysis procedures of slopes are usually implicit and cannot be solved by first-order second-moment approach. A new reliability analysis approach was presented based on three-dimensional Morgenstem-Price method to investigate three-dimensional effect of landslide in stability analyses. To obtain the reliability index, Support Vector Machine （SVM） was applied to approximate the performance function. The time-consuming of this approach is only 0.028% of that using Monte-Carlo method at the same computation accuracy. Also, the influence of time effect of shearing strength parameters of slope soils on the long-term reliability of three-dimensional slopes was investigated by this new approach. It is found that the reliability index of the slope would decrease by 52.54% and the failure probability would increase from 0.000 705% to 1.966%. In the end, the impact of variation coefficients of c andfon reliability index of slopes was taken into discussion and the changing trend was observed.

Efficient computation for dynamic responses of systems with time-varying characteristics

Based on Neumman series and epsilon-algorithm, an efficient computation for dynamic responses of systems with arbitrary time-varying characteristics is investigated. Avoiding the calculation for the inverses of the equivalent stiffness matrices in each time step, the computation effort of the proposed method is reduced compared with the full analysis of Newmark method. The validity and applications of the proposed method are illustrated by a 4-DOF spring-mass system with periodical time-varying stiffness properties and a truss structure with arbitrary time-varying lumped mass. It shows that good approximate results can be obtained by the proposed method compared with the responses obtained by the full analysis of Newmark method.

The Historical Position and Value Dimensions of Human Rights Civilization

Human beings are the mainstay and the ultimate goal of civilization.The history of human civilization is a continuous struggle to realize the respect,liberation,protection,and development of humanity.Human rights are an achievement of humanity and a symbol of progress,and the human rights civilization is an important component of human civilization.Understanding and interpreting human rights from the perspective of human rights civilization means that human rights are not only a concept or an idea but also a grand historical and long-term social practice.Up to now,the development of human rights civilization has roughly experienced four awakening eras:initialization,revolution,popularization,and globalization.In terms of its value dimensions,it has the characteristics of progressiveness,diversity,commonality,inclusiveness,indivisibility,openness,and so on.The historical position of human rights civilization and the development of its value dimensions have shown to the world that human rights are the common wealth of humanity,and human rights belong to all mankind;human rights are historical,concrete,and developmental;the concept of human rights is constantly evolving,and its connotations and categories are constantly expanding;achieving the free and well-rounded development of every person is the highest value realm of human rights civilization.The Chinese modernization endows Chinese civilization with modern strength and opens up new horizons for human rights civilization.The new pattern of human rights civilization to be created by Chinese modernization not only possesses the common characteristics of human rights civilization but also enjoys Chinese characteristics based on its own national conditions,enriching and developing the diversity of human rights civilization for all mankind.

Fixed-Time Adaptive Time-Varying Matrix Projective Synchronization of Time-Delayed Chaotic Systems with Different Dimensions

This paper deals with the fixed-time adaptive time-varying matrix projective synchronization(ATVMPS)of different dimensional chaotic systems(DDCSs)with time delays and unknown parameters.Firstly,to estimate the unknown parameters,adaptive parameter updated laws are designed.Secondly,to realize the fixed-time ATVMPS of the time-delayed DDCSs,an adaptive delay-unrelated controller is designed,where time delays of chaotic systems are known or unknown.Thirdly,some simple fixed-time ATVMPS criteria are deduced,and the rigorous proof is provided by employing the inequality technique and Lyapunov theory.Furthermore,the settling time of fixed-time synchronization(Fix-TS)is obtained,which depends only on controller parameters and system parameters and is independent of the system’s initial states.Finally,simulation examples are presented to validate the theoretical analysis.

Research of the Characteristic Dimension of the Transfers during the Convective Drying of the Sweet Potato for the Parallelepipedic and Spherical Shapes

The aim of this work was to determine the characteristic dimension governing transfers during convective drying. Parallelepipedic and cylindrical form of sweet potato was used. For the parallelepipedic form P_L-l-e, the thickness e is set to 1 cm while the length L and the width l are varying. The results show that the variation of the other dimensions other than the thickness e does not influence the transfers in a considerable way. The same observation is made for the cylindrical samples c_H-R by keeping the radius R constant. This present work therefore allows us to conclude that the thickness of the parallelepiped shaped samples and the radius of the cylindrical shapes, all being the smallest dimensions, characterize the transfers.

Chaotic characteristics of electromagnetic emission signals during deformation and fracture of coal

Electromagnetic emission(EME) is a kind of physical phenomenon accompanying the process of deformation and fracture of loaded coal and rock and it is of importance in quantitatively analyzing its characteristics.This will reveal the process of deformation and fracture of coal and predicting dynamic disasters in coal mines.In this study,the G-P(Grassberger and Procaccia) algorithm,calculation steps of the(if only 1 dimension) correlation dimension of time series and the identification standards of chaotic signals are introduced.Furthermore,the correlation dimensions of EME and the acoustic emission(AE) signals of time series during deformation and fracture of coal bodies are calculated and analyzed.The results show that the time series of pulses number of EME and the time series of AE count rate are chaotic and that the saturation embedding dimensions of a K3 coal sample are,respectively,5 and 6.The results can be used to provide basic parameters for predicting of EME and AE time series.

Cross-scale characteristics of backfill material using NMR and fractal theory

This paper analyzed the pore structure, quantified the pore fractal dimension, calculated the grading index(GI) of mixed aggregate, and studied the relationship among GI, pore structure, and strength to describe the cross-scale characteristics of backfill, which is made from stone powder and cemented tailing. A series of experiments were conducted on stone powder cement tailings backfill(SPCTB). The GI formulas for mixed aggregates, containing stone powder and tailings, were derived based on the Füller theory. The nuclear magnetic resonance(NMR) fractal dimensions of backfills were derived using fractal geometry principles. Compared to the mesopore and macropore fractal dimensions, the correlation between micropore fractal dimension and macro-properties in terms of NMR porosity, pore structure complexity, uniaxial compression strength(UCS), and GI is the most significant. Macropore fractal dimension is generally correlated with UCS and GI and the other properties such as the shape of mixed aggregates also have an impact on fractal dimension. However, mesopore fractal dimension has no obvious relationship with macro-properties. Finally, the relationship between GI and UCS was studied, which contributed to improving backfill’s strength and optimizing gradation.

Urban Spatial Expansion Characteristics in China’s Rapid Urbanization Region—A Case Study of SXC Region

Urban spatial expansion characteristics are the responses of urbanization acts on the geographical space. Analyzing the characteristics can reveal the process of urban expansion and mechanism which is one of useful methods to find out the sustainable land use strategy balancing development and protection. In this paper, two main methods have been deployed in analyzing the spatial expansion characteristics of rapid urbanization region. One is the expansion index method and the other is fractal dimension method. And the results show that town-level urban sprawl has increased in a non-linear way since 1985, and even the increments of the urban expansion intensity are fluctuated. Morphology transformation from scatter to concentration is common phenomenon in the process of urbanization in the towns. From the morphology point of view, downtowns are more homogenous than towns with less variation. The concentration is the leading development trend in downtowns. And the more distance from the downtown is, the more spatial pattern morphology will be observed. These characteristics indicate that macro-scale policies of economic development and land use management have great impacts on the formation and characteristics of spatial patterns of urban dynamic patterns.

RESEARCH ON FRACTAL CHARACTERISTICS OF URBAN TRAFFIC NETWORK STRUCTURE BASED ON GIS

Traffic network is an importance asp ect of researching controllable parameters of an urban spatial morpholo-gy.Based on GIS,traffic network str ucture complexity can be understood by using fractal geometry in which th e length-radius dimension describes change of network density,and ramification-radius dimension describes complexity and accessibility of urban network.It i s propitious to analyze urban traffic network and to understand dynamic c hange process of traffic network using expanding f ractal-dimension quantification.Meanwhile the length-radius dimension and ramifica-tion-radius dimension could be rega rd as reference factor of quantitative describing urban traffic network.

The Chinese Expression of the Right to Subsistence:The Progressive Disclosure of the Dual Dimensions

Dedicated to the independence and prosperity of the country and the happiness of the people,the Communist Party of China has continuously enriched and developed the human rights system with Chinese characteristics during a century of arduous efforts.The right to subsistence,as the primary basic human right,is expressed from dual dimensions:the international dimension and the domestic dimension.However,the current Chinese human rights discourse hasn’t paid enough attention to the international dimension of the right to subsistence,and its content at the domestic dimension needs further clarification.This not only makes it difficult to provide a sound theoretical basis and development direction for the practices of the right to subsistence but also directly affects the integrity of the human rights system with Chinese characteristics,which is not conducive to using our human rights discourse to disseminate China’s achievements and gain international recognition.Therefore,it is vital to further improve the theory construction of the dual dimensions of the right to subsistence in the human rights system with Chinese characteristics.With the country as the main form and carrier,the international dimension of the right to subsistence originates from the people’s demands emerging from the domestic level and ending at the international level.It aims to be able to stand in the international community with dignity and possess good conditions and environments at home and abroad for the people to exercise and protect their rights.The domestic dimension of the right to subsistence centers on each individual,takes development as the measurement of human rights,and looks at the initial stage of the development axis.The progress from the domestic dimension of the right to subsistence to the right to development is achieved by satisfying the underlying needs for people’s subsistence.This also reflects the progressive deepening of emerging from the inside,responding from the outside,and then moving from the outside to the inside.

Morphology characteristics of joint surface in rock mass

In order to quantify the characteristics of the surface of jointed rock mass,new equipment,the three-dimensional laser surface topography instrument,was used to accurately measure surface morphology of joints.Scan pictures and parameters were obtained to describe the rock joint surface characteristics,for example,the height frequency of surface,and mean square roughness.Using the method of fractal dimension,the values of joint roughness coefficient(JRC) were calculated based on the above parameters.It could access to the joint surface rock sample morphology of the main parameters of characteristic.The maximum peak height is 2.692 mm in the test joint plane.The maximum profile height is 4.408 mm.JRC value is 6.38 by fractal dimension computing.It belongs to the smooth joint surface.The results show that it is a kind of the effective method to quantitatively evaluate the surface topography by the three-dimensional laser surface topography instrument and the fractal dimension method.According to the results,during the process of underground large-scale mining,safe measures to prevent slip failure of the joint plane by controlling surface tension and shear mechanical response were proposed.

Investigation on Fractal Characteristics of Disintegration Process and Strength of Rockfill under Water Pressure

The paper aimed to investigate internal mechanics between disintegration of the rockfill material and stability of the dam, and further provide scientific evidence for the design of rockfills, through the conducted disintegration of water pressure and triaxial test to analyze fractal characteristics, strength and deformation of the rockfill in whole disintegration procedure. As the results that the water pressure was low 0.2 MPa, the increasing water pressure would delay the disintegration rate of rockfill;while the water pressure was above 0.2 MPa, it would promote the disintegration rate of the rockfill. In addition, in the disintegration process, the cohesion force of rockfill rapidly slowed down at the beginning and then gradually increased. The internal friction angle increased gradually during the whole disintegration process. Furthermore, when the water pressure increased from 0 MPa to 0.6 MPa, the partial stress firstly decreased to a minimum level when the water pressure was 0.2 MPa, and then increased gradually with water pressure.

Research on Pore Structure and Fractal Characteristics of Tight Sandstone Reservoir Based on High-Pressure Mercury Injection Method

Pore structure is the key element of tight sandstone reservoir, which restricts the accumulation and flow of oil and gas in the reservoir. At present, reservoir pore structure is the focus and difficulty of unconventional oil and gas exploration and development research. The tight sandstone reservoir in the Chang 4 + 5 member of the Upper Triassic Yanchang Formation is the main reservoir for oil and gas exploration in G area. At present, there is little research on its pore structure and fractal characteristics, which to some extent affects the progress of exploration and development. This paper selects the tight core samples of the Chang 4 + 5 member in the southern edge of the Ordos Basin, and based on the high-pressure mercury intrusion experiment, uses fractal theory to study the pore structure and fractal characteristics of the reservoir in the study area, thus providing theoretical basis for the evaluation and exploration and development of the Chang 4 + 5 tight reservoir in the G area. The research results show that the lithology of the Chang 4 + 5 tight sandstone reservoir in the southern edge of the Ordos Basin is mainly feldspathic sandstone, with the highest feldspar content, followed by quartz, and the clay mineral is mainly chlorite. The reservoir has poor physical properties and strong heterogeneity. There are three main fractal characteristics in Chang 4 + 5 reservoir in G area: the fractal curve of Type I reservoir sample is in two segments, the relatively large pore has certain fractal characteristics, the pore structure is relatively regular, and the heterogeneity is weak;Relatively small pores have no fractal characteristics and pore structure is irregular. The fractal curve of Type II reservoir samples shows a three-segment pattern, and each pore size range has certain fractal characteristics, and it gradually gets better with the increase of pore size. The fractal curve of Type III reservoir samples presents a similar one-segment pattern, and the fractal dimension exceeds the upper limit of 3. It is considered that the full pore size of this type of reservoir does not have fractal characteristics, the pore throat is completely irregular or the surface is rough, and the heterogeneity is very strong.

新时代中国特色马克思主义文论建设的四个维度

新时代中国特色马克思主义文论建设是一项前所未有的世纪工程,需要进行艰苦卓绝的探索。构建新时代中国马克思主义文论话语必须坚持立足国情和文艺实践,在回应现实挑战中发现问题,坚持“不忘本来,吸收外来,面向未来”的原则高效构建。一方面,坚持马克思主义基本原理和已被实践证明的真理性理论;另一方面,坚持吸收和借鉴马克思主义理论之外一切有益的理论资源;同时,要突出理论的创新性、前瞻性及对现实文艺实践的指导作用。新时代中国特色马克思主义文论应在上述四个维度的有机统一中,为世界文明和人类命运共同体构建贡献中国智慧和中国方案。

砂岩剪切破裂面形貌特征及粗糙度各向异性

岩体破裂面的形态特征是影响其剪切滑移破坏的重要因素,法向应力是岩体剪切破裂面形态特征的重要影响因素.为研究法向应力对砂岩剪切破裂面形貌特征和粗糙度的影响,首先开展了砂岩双面剪切试验,获得不同法向应力作用下砂岩剪切破裂面,然后对直剪试验中形成的剪切破裂面进行三维光学扫描,最后对不同法向应力作用下砂岩剪切破裂面进行三维重构.分析了法向应力对剪切破裂面粗糙高度特征参数的影响,基于各向异性参数研究了砂岩剪切破裂面粗糙度各向异性特征,研究了砂岩剪切破裂面分形特征与粗糙度的关系.结果表明,砂岩剪切破裂面粗糙高度期望值、标准差、均值和最大起伏差都随法向应力的增大而增大;剪切破裂面粗糙度表现出显著的各向异性,随着与剪切方向夹角的增大,砂岩剪切破裂面粗糙度先减小后增大;法向应力为压应力时,剪切破裂面粗糙度在与剪切方向成75°~90°时取得最小值;剪切破裂面粗糙度极差和各向异性参数随法向应力的增大逐渐增大,剪切破裂面各向异性特征增强;砂岩剪切破裂面分形维数与粗糙度呈幂函数关系.