Gradient Analysis of Land Utilization and Landscape Pattern Based on the Buffer Zone in South Guangzhou City

Under the background of the 'Southwardly Development' of Guangzhou City,this paper chooses Panyu District as the research object and uses the 2005 land use data to quantitatively analyze the landscape layout and its change in the study area based on the support of GIS and Fragstats through combining landscape index and gradient analysis.The results show that it is feasible to show urbanization and the change of the spatial pattern of urban landscape through utilizing gradient analysis and landscape index.Over the course of 'Southwardly Development',the urbanization level of Panyu District has been enhanced unceasingly.And the landscape spatial patterns of different land uses and their variation characteristics are obviously different.

Electrohydromechanical analysis based on conductivity gradient in microchannel

Fluid manipulation is very important in any lab-on-a-chip system. This paper analyses phenomena which use the alternating current （AC） electric field to deflect and manipulate coflowing streams of two different electrolytes （with conductivity gradient） within a microfluidic channel. The basic theory of the electrohydrodynamics and simulation of the analytical model are used to explain the phenomena. The velocity induced for different voltages and conductivity gradient are computed. The results show that when the AC electrical signal is applied on the electrodes, the fluid with higher conductivity occupies a larger region of the channel and the interface of the two fluids is deflected. It will provide some basic reference for people who want to do more study in the control of different fluids with conductivity gradient in a microfluidic channel.

SPATIAL GRADIENT ANALYSIS OF URBAN GREEN SPACES COMBINED WITH LANDSCAPE METRICS IN JINAN CITY OF CHINA

Urban green spaces have been arisen growing concern responded to the social and environmental costs of urban sprawl. A wide range of planning and policies has been and/or will be designed to protect urban green spaces and optimize their spatial pattern. A better design or planning of urban green space can make a major contribution to quality of environment and urban life, and furthermore can decide whether we can have a sustainable development in the urban area. Information about the status quo of urban green spaces can help planners design more effectively. However, how to quantify and capture such information will be the essential question we face. In this paper, to quantify the urban green space, a new method comprising gradient analysis, landscape metrics and GIS was developed through a case of Jinan City. The results demonstrate: 1) the gradient analysis is a valid and reliable instrument to quantify the urban green space spatial pattern precisely; 2) using moving window, explicit landscape metrics were spatially realized. Compared with quantifying metrics in the entire landscape, it would be better to link pattern with process and establish an important basis for analyzing the ecological and socioeconomic functions of green spaces.

Variations of plant life form diversity along the Northeast China Transect and its direct gradient analysis

Plant life form diversity and its direct gradient analysis on a larger scale climate change gradient were tested, based on the data from Northeast China Transect platform. The results showed that the species numbers, life form richness and life form diversity were relative higher at the eastern forests and the ecotone between typical vegetation, while those on the meadow grasslands and typical steppes were lower. Although plant life forms can reflect the climate variations, life form diversity is not consistent with the major global gradient along the NECT.

Vibration and wave propagation analysis of twisted micro-beam using strain gradient theory

In this research, vibration and wave propagation analysis of a twisted micro- beam on Pasternak foundation is investigated. The strain-displacement relations （kine-matic equations） are calculated by the displacement fields of the twisted micro-beam. The strain gradient theory （SGT） is used to implement the size dependent effect at micro-scale. Finally, using an energy method and Hamilton＇s principle, the governing equations of motion for the twisted micro-beam are derived. Natural frequencies and the wave prop- agation speed of the twisted micro-beam are calculated with an analytical method. Also, the natural frequency, the phase speed, the cut-off frequency, and the wave number of the twisted micro-beam are obtained by considering three material length scale parameters, the rate of twist angle, the thickness, the length of twisted micro-beam, and the elastic medium. The results of this work indicate that the phase speed in a twisted micro-beam increases with an increase in the rate of twist angle. Moreover, the wave number is in- versely related with the thickness of micro-beam. Meanwhile, it is directly related to the wave propagation frequency. Increasing the rate of twist angle causes the increase in the natural frequency especially with higher thickness. The effect of the twist angle rate on the group velocity is observed at a lower wave propagation frequency.

Orthogonal wavelet analysis of counter gradient transport phenomena in turbulent asymmetric channel flow

In this paper four families of orthogonal wavelets are applied to analyze the turbulent counter gradient transport phenomena in fully developed asymmetric channel flows. The results show that: (1) In the instance of counter gradient transport, the principal scale of the coherent structure is responsible for the strong local counter gradient transport; (2) Counter gradient transport phenomena have a strong effect on the intermittency of turbulence; (3) Non-Gaussian part of the principal coherent structure is essential for counter gradient transport phenomena.

Analysis of limitations on recovery of gravity field based on satellite gravity gradient data

Although satellite gravity gradient data plays a great role in determining short-wavelength part of static gravity field model,accuracy of the long-wavelength part of gravity field model recovered by them are poor,which leads to only a few applications in time-variable gravity investigation.The reason is that some factors limit the accuracy of the gravity field recovered using gradient data,including accuracy of the gravity gradient observations,measurement bandwidth(MBW)of gradiometer,satellite inclination,etc.This paper aims at analyzing the influence of these limitations on gravity field recovery and discusses the possibility of time-variable gravity field detection by using gravity gradient observations.Firstly,for arbitrary satellite orbit inclination,we give the frequency distributions of all the components of gravity gradients(i.e.Txx;Tyy;Tzz;Txy;Txz and Tyz,).The results show that the maximum frequency of each component of the gravity gradients is the same,i.e.l=Ts(l is degree of the gravity field model,Ts is the orbital periods),and it is not influenced by the inclination of the satellite orbits.Secondly,the paper gives a theory proof to explain why only the low orders of the coefficients are influenced by polar gaps.Big polar gaps are experimented by a numerical test with inclination of 45°.Finally,considering that the measurement bandwidth can be expanded and accuracy of gradient observations can be improved by superconducting gravity gradiometer(SGG)compared to gradiometer used in Gravity field and steadystate Ocean Circulation Explorer(GOCE),the possibility of detecting time-variable gravity using gravity gradient observations is discussed.The results show that the SGG creates errors in MBW with magnitude of 0.014 m E,which is smaller than the magnitude of the time-variable gravity gradient signals(i.e.,0.02 m E)derived from Gravity Recovery and Climate Experiment(GRACE)gravity field models.This indicates the potential of SGG in time-variable gravity detection.

Impacts of Transportation Arteries on Land Use Patterns in Urbanrural Fringe: A Comparative Gradient Analysis of Qixia District, Nanjing City, China

Integrated transportation and land use studies are of major interest to planners because they consider the interaction between transportation development and land use change. Quantifying the impact of transport infrastructure on land use change is necessary for evaluating the role of transportation development in the process of land use and land cover change in the urban-rural fringe. Taking Qixia District of Nanjing City, Jiangsu Province, China as a typical urban-rural fringe area, this paper analyzes the patterns and charac- teristics of land use change along three major transportation arteries using land use data from 2000 and 2008. We examine the spatial differentiation and gradient of land use pattern around railway, expressway, and highway corridors to investigate whether land use change in the urban-rural fringe is related to distance from transportation arteries and to clarify the varying impacts of different forms of transport infrastructure on land use patterns. We find that construction land generally tends to be located close to major transportation arteries, and that railways have the most obvious influence on land use change in the urban-rural fringe, while the impact of expressways was not significant. We conclude that there exists a causal relationship between the presence of transportation arteries and land use change in the urban-rural fringe, but this relationship varies across different types of linear transnort infrastrncnlre.

Flow pattern analysis of linear gradient flow distribution

This paper uses the Oseen transformation to solve the differential equations governing motion of the vertical linear gradient flow distribution close to a wall surface. The Navier-Stokes equations are used to consider the inertia term along the flow direction. A novel contour integral method is used to solve the complex Airy function. The boundary conditions of linear gradient flow distribution for finite problems are determined. The vorticity function, the pressure function, and the turbulent velocity profiles are provided, and the stability of particle trajectories is studied. An Lx-function form of the third derivative circulation is used to to simplify the solution. Theoretical results are compared with the experimental measurements with satisfactory agreement.

Finite Element Analysis of Thermal Stresses in Ceramic/Metal Gradient Thermal Barrier Coatings

This paper studied the thermal stresses of ceramicl metal gradient thermal barrier coating which combines the conceptions of ceramic thermal barrier coating （TBC） and functionally gradient material （FGM）. Thermal stresses and residual thermal stresses were calculated by an ANSYS finite element analysis software. Negative thermal expansion coefficient method was proposed and element birth and death method was applied to analyze the residual thermal stresses which have non-uniform initial temperature field. The numerical results show a good agreement with the analytical results and the experimental results.

Drug-eluting balloons versus new generation drug-eluting stents for the management of in-stent restenosis: an updated meta-analysis of randomized studies

Background New-generation drug-eluting stents (DES) was more effective in the treatment of in-stent restenosis (ISR) compared with the first-generation DES. Drug-eluting balloons (DEB) and new-generation DES had been available strategies in treatment of bare-metal stents/DES ISR (BMS/DES-ISR). Six new randomized trials have recently examined the angiographic outcomes and one-year clinical outcomes of DEB and new generation DES in BMS/DES-ISR. However, the optimal management for BMS/DES-ISR lesions remains controversial. Methods We searched the randomized clinical trials evaluating the angiographic outcomes and one-year clinical outcomes of DEB and new-generation DES in patients with BMS/DES-ISR. The primary endpoints were the angiographic outcomes, including the minimal luminal diameter (MLD), diameter stenosis %(DS%), late lumen loss (LLL), and binary restenosis (BR). Results A total of six randomized clinical trials with 1177 BMS/DES-ISR patients were included in our meta-analysis. For angiographic outcomes, there were significantly less MLD and more DS% with DEB compared to new-generation DES (MLD: MD =?0.18, 95% CI:?0.31– ?0.04, P < 0.001;DS%: MD = 5.68, 95% CI: 1.00–10.37, P < 0.001). Moreover, for one-year clinical outcomes, DEB was associated with a significant increase risk in target lesion revascularization (TLR)(RR = 2.93, 95% CI: 1.50–5.72, P = 0.002). However, DEB was associated with higher risks of major adverse cardiac event, target vessel revascularization, TLR, BR, and more DS% only in DES-ISR group. Conclusions DEB and new-generation DES have the similar clinical efficacy for the treatment of BMS-ISR. However, DES showed more MLD, less DS%, and a decreased risk of TLR for the treatment of DES-ISR.

Gradient Analysis of Urbanization Pattern Based on Class-level Landscape Metrics for Shanghai Region

The spatial pattern of urbanization in the Shanghai metropolitan area is quantified with GIS-based land use data set and gradient analysis of landscape metrics. A number of landscape metrics were computed along a 64 Ion long and 6 km wide west-east transect and another 66 km long and 6 km wide south-north transect. The results of transect analysis with class-level metrics showed that the spatial pattern of urbanization could be reliably quantified using landscape metrics with a gradient analysis approach, and the location of the urbanization center could be identified precisely and consistently with multiple indices of the landscape metrics used in this study. Different land use types exhibited distinctive, but not necessarily unique, spatial signatures that were dependent on specific landscape metrics. These results seemed to characterize the urban core of the Shanghai metropolitan area rather accurately and precisely.. Agriculture patches were abundant and less fragmented; the urban land use types were extensive, having many small patches and highly fragmented.

A GRADIENT ANALYSIS & MODELING OF THE NECT FOR GLOBAL CHANGE STUDY

The North East China Transect (NECT) is an exemplary region of landmass running along the line of 43°30′ North Latitude and caught between 112° and 130°30′ East Longtitude, and is being sampled by the International Geosphere-Biosphere Program (IGBP) for today’s study on global change. So far, it has already been listed in the first set of IGBP-sponsored transects, becoming a key theatre and "hot spot" for probing terrestrial ecosystems. In terms of biota, the nearly 1,600-kilometre-long tract is located in a mid-latitude zone, featuring a vegetational transition from a temperate timberland of evergreen coniferous forests and broadleaved deciduous forests to a mild-temperate steppe. According to the norms of biome types, it consists of three subzones: meadow steppe, typical steppe and desert steppe in a continuous east-to-west spatial sequence. There are four ecological stations supported by a great number of permanent samples, long-term plots and an enormous build-up of experimental data along

Impact Performance Research of Re-Entrant Octagonal Negative Poisson’s Ratio Honeycomb with Gradient Design

Based on the traditional re-entrant honeycomb,a novel re-entrant octagon honeycomb(ROH)is proposed.The deformation mode of the honeycomb under quasi-static compression is analyzed by numerical simulation,and the results are in good agreement with the experimental ones.The deformation modes,mechanical properties,and energy absorption characteristics of ROH along the impact and perpendicular directions gradient design are investigated under different velocities.The results indicated that the deformation mode of ROH is affected by gradient design along the direction of impact and impact speed.In addition,gradient design along the direction of impact can increase the initial peak stress of ROH and accelerate its densification phase.Gradient design perpendicular to the impact direction can enhance the energy absorption performance of ROH,especially for ROH,with wall thickness increasing from the inside outwards.Compared to ROH with uniform wall thickness at the same relative density,ROH with a gradient design can increase the plateau stress by over half.With the elevation of impact velocity,the plateau stress and specific energy absorption exhibit an upward trend,aligning with the dynamic performance pattern observed in conventional honeycombs.The results can be used as a reference for the design and application of honeycomb and provide a new idea for developing more efficient and reliable energy-absorbing materials.

ORDINATION AND GRADIENT ANALYSIS OF CONIFEROUS FOREST IN DAXINGANLING

In this paper,the quantitative approach is applied on the study of coniferous forestbased on the data which were collected by the field investigation in Daxinganling region.The mainpurpose is objectively to show the position of communities in the space and the relationship be-tween the community and environment.By means of ordination,it is found that dahurian larch for-est,mongolian scots pine forest and korean fir forest lie in different positions. Gradient analysis ofthree dominant types of conigerous forest has revealed the difference of ecological amplitude,thedifference is one of the important reasons that determine the different communities in the differentenvironment.

Thermoelastic analysis of functionally graded annulus with arbitrary gradient

A thermoelastic problem of a circular annulus made of functionally graded materials with an arbitrary gradient is investigated. Different from previous works, our analysis neither requires a special form of the gradient of material properties nor demands partitioning the entire structure into a multilayered homogeneous structure. Instead, we propose a new method for solving the thermoelastic problem of a functionally graded circular annulus by transforming it to a Fredholm integral equation. The distribution of thermal stresses and radial displacement can be obtained by solving the resulting equation. Illustrative examples are given to show the effects of varying gradients on the thermal stresses and radial displacement for given temperature changes at the inner and outer surfaces. The results indicate that the thermal stresses can be relaxed for specified gradients, which is beneficial to design an inhomogeneous annulus to maintain structural integrity.

A note on a family of proximal gradient methods for quasi-static incremental problems in elastoplastic analysis

Accelerated proximal gradient methods have recently been developed for solving quasi-static incremental problems of elastoplastic analysis with some different yield criteria.It has been demonstrated through numerical experiments that these methods can outperform conventional optimization-based approaches in computational plasticity.However,in literature these algorithms are described individually for specific yield criteria,and hence there exists no guide for application of the algorithms to other yield criteria.This short paper presents a general form of algorithm design,independent of specific forms of yield criteria,that unifies the existing proximal gradient methods.Clear interpretation is also given to each step of the presented general algorithm so that each update rule is linked to the underlying physical laws in terms of mechanical quantities.

Simulation of X-ray Diffraction Line Broadening Caused by Stress Gradients and Determination of Stress Distribution by Fourier Analysis

Different physical, mechanical and chemical processes, such as： ion implantation, oxidation, nitridation and others create on the surface of materials residual stress state, characterized by high level and strong gradient. X-ray diffraction method widely used for stress measurements has some difficulties in interpretation of experimental data, when the depth of X-ray penetration is compared with thickness of surface layer where inhomogeneous stress distribution is localized. Early it has been shown by authors that diffraction line broadening occurs when analyzed surface is characterized by strong gradient. The interest to study the diffraction line broadening is connected to the possibility of obtaining information about parameters of surface stress distribution. In the present paper the convolution and deconvolution concepts of Fourier analysis were applied to study X ray diffraction line broadening caused by surface stress gradients. Developed methodology allows determining of stress distribution in superficial layers of materials.

Efficacy of Short-term Dual Antiplatelet Therapy after Implantation of Second-generation Drug-eluting Stents:A Meta-analysis and Systematic Review

Objective The benefit of short-term dual antiplatelet therapy(DAPT) following second-generation drug-eluting stents implantation has not been systematically evaluated. To bridge the knowledge gap,we did a meta-analysis to assess the efficacy of ≤6 months versus ≥12 months DAPT among patients with second-generation drug-eluting stents. Methods We searched online databases and identified randomized controlled trials that assess the clinical impact of short-term DAPT(≤6 months) published before March 3,2016. The efficacy endpoints included the incidence of all-cause death,myocardial infarction,cerebrovascular accidents,and definite or probable stent thrombosis. Safety endpoint defined as major bleeding was also evaluated and discussed. Results We included 5 trials that randomized 9473 participants(49.8%,short-term DAPT duration vs. 50.2%,standard duration). A total of 9445(99.7%) patients reported the efficacy endpoints,and the safety endpoint was available from 4 studies(n=8457). There was no significant difference in efficacy endpoints between short-term and standard DAPT duration(≥12 months) [risk ratio(RR) 0.96; 95% confidence intervals(CI),0.80-1.15]. Short-term DAPT duration did not significantly increase the individual risk of all-cause death,myocardial infarction,cerebrovascular accidents,or definite or probable stent thrombosis. Although short-term DAPT obviously reduced risk of major bleeding compared with standard DAPT(RR 0.53; 95% CI,0.29-0.96),significant publication bias was found when accessing the safety endpoint of the 4 studies(Egger's test,P=0.009). Conclusions The efficacy of short-term DAPT was comparable with that of standard duration DAPT.DAPT less than 6 months may be appropriate for patients receiving second-generation drug-eluting stents implantation.

Assessment of Vertical Magnetic Gradient Data of Tuzla Fault Using Boundary Analysis and 3-D Inversion Techniques

The magnetic prospection is one of the most useful methods to determine buried geological structures such as shallow fracture zones. The investigation of vertical and horizontal gradient and total magnetic field variations over geological structures, which have been used for many years, may reveal their locations, geometries and physical characteristics. In this study, a proposed iterative 3-D rectangular prismatic model inversion algorithm was modified to interpret vertical magnetic gradient data defining the boundaries and the physical parameters of the anomalous structure. Vertical magnetic gradient measurements were carried out at the Tuzla fault, an active fault system located along NE-SW direction in Izmir (Turkey). Boundary analysis studies were applied to data in order to obtain boundaries of the structures, afterwards the inversion process was carried out considering these geometries. As a result, location, direction and other physical and geometrical features of the fault are achieved.