Radial Variation in Sap Flux Density as a Function of Sapwood Thickness in Two Eucalyptus ( Eucalyptus urophylla ) Plantations

Radial variation in sap flux density (SFD) as a function of sapwood thickness is of importance in accurately estimating sap flux through sapwood area which, in turn, decides the precision of heat pulse application. However, until now, only a few studies have evaluated the magnitude and significance of sampling errors associated with radial gradients in SFD, which were based on the small monitoring measurement data from a few trees. Based on one year of heat pulse observation of two 3 - 4 years old Eucalyptus urophylla S. T.,P Blake plantations in Leizhou Peninsula, Guangdong Province, China, a way of data processing was developed to treat with the lots of SFD data measured from 39 trees. It was found that the radial variation in SFD as a function of sapwood thickness in the two eucalyptus plantation sites could be expressed as y = 3. 667 5x(3) - 7.295 5x(2) + 3.682 6x + 0. 567 4 (R-2 = 0. 939 1, n = 80, P = 0.01), where y is the ratio of SFD of a sensor to the average of four data in different depths, x is the ratio of a sensor depth to tire radial sapwood thickness. It was the same (as in the following equation) in Jijia site, y = 5.006 2x(3) - 9.116 1x(2) + 4. 454 4x + 0.463 4 (R-2 = 0. 806 9, n = 72, P = 0.01) in Hetou site. From cambium to heartwood, SFD showed some increases at first and then decreases continuously. However, because die trees were very young, the maximum SFD was only 0. 33 - 0. 36 times more than the minimum.

Natural Variation of Leaf Thickness and Its Association to Yield Traits in indica Rice

Leaf thickness is an important morphological trait in rice. Its association to the yield potential, as of now has not been documented because of the shortage of the equipment which could conveniently measure the leaf thickness in rice. In this study, the thickness of top three leaves of 208 cultivars had been determined by a nondestructive rice leaf thickness instrument for the research of the natural variation of leaves thickness and its association to yield traits in indica rice. The results showed that the flag leaf was the thickest, and the 2nd leaf was thicker than the 3rd leaf. Analysis of variance indicated the existence of wide genetic diversity of leaf thickness among the investigated indica rice genotypes. The tight correlation among the thicknesses of the top three leaves means that the leaf thickness traits share one genetic control system. Leaf thickness had a significant positive correlation with leaf length and a positive correlation with leaf width, indicated that thicker leaf was beneficial to increasing the single leaf area. The results of correlation analysis revealed that thicker leaf should be profitable to the leaf erection, higher numbers of grains per panicle and higher grains weight per panicle. However, the significantly negative correlation between leaf thickness and number of panicles per plant counteracted the profitability from increased grains weight per panicle, so that the correlations of the thicknesses of the top three leaves to yield and biomass were positive but not significantly. It has made great progress in the genetic improvement of leaves thickness in inbred indica rice breeding in Guangdong Province, China, since the 1990s.

Study on Dragline-Bulldozer Operation with Variations in Coal Seam Thickness

The dragline is one of the most promising surface mining machines in China. This paper studies the interac-tion between the working bench advancing speed and the stripping volume with variation in coal seam thickness. Ad-justing the bulldozing volume (depth) and/or changing the dragline bench height are proposed as means to ensure a smooth and economical mining operation. When the coal seam is getting thicker it is recommended to reduce the bull-dozing volume (depth) for a higher dragline efficiency. When the coal seam is getting thinner it is recommended to in-crease the bulldozing volume (depth) to ensure the dragline can work at the proper bench height.

Variations in bark thickness and sapwood density of Calophyllum inophyllum provenances in Australia and in Sri Lanka

Sapwood density and bark thickness of Calophyllum inophyllum L. （a multipurpose durable timber species） were studied in various locations in Northern Australia and in Sri Lanka. Measurements were taken non-destructively by using core sampling and bark gauge. From each provenance, 4–15 mature trees having girth at breast height over bark （GBHOB） at 100–150 cm were selected on the basis of the population size. Significant （p0.05） hemispheric and provenance variations in bark thickness were found. Variations in the bark thickness are influenced by environmental variables. Variations in sapwood density were less pronounced compared to that of bark thickness. Variations in sapwood density are likely to be governed by genotypic variations.

Modeling and solving for transverse vibration of gear with variational thickness

A analyzed model of gear with wheel hub, web and rim was derived from the Mindlin moderate plate theory. The gear was divided into three annular segments along the locations of the step variations. Traverse displacement, rotation angle, shear force and fiexural moment were equal to ensure the continuity along the interface of the wheel hub, web and rim segments. The governing differential equations for harmonic vibration of annular segments were derived to solve the gear vibration problem. The influence of hole to diameter ratios, segment thickness ratios, segment location ratios, Poisson ratio on the vibration behavior of stepped circular Mindlin disk were calculated, tabletted and plotted. Comparisons were made with the frequencies arising from the presented method, finite elements method, and structure modal experiment. The result correlation among these three ways is very good. The largest error for all frequencies is 5.46%, and less than 5% for most frequencies.

The diurnal variation pattern of choroidal thickness in macular region of young healthy female individuals using spectral domain optical coherence tomography

AIM： To investigate the pattern of diurnal variations of choroidal thickness of macular region of healthy individuals. ~ METHODS： A prospective study of 32 healthy female subjects was conducted. Each subject underwent 1） a questionnaire on daily schedule, 2） the Pittsburgh Sleep Quality Index questionnaire （PSQI）, and 3） ocular examinations including an eye dominance test, fundus photography, and sequential optical coherence tomography （OCT） imaging, on two separate days at five fixed 3h time intervals. Choroidal thickness was measured by two masked graders. RESULTS： A significant diurnal variation of choriodal thickness at fovea （P〈0.001）, at 500 μm nasal （P〈0.001）, temporal to fovea （P=0.01） or 1500 μm nasal to fovea （P= 0.001） was observed. The median choroidal thickness peaked at 11：00 at fovea （P=0.01）, at 500μm nasal （P = 0.009） and temporal （P=0.03） to fovea. The median amplitude of foveal choroidal thickness was 20.5 pm （13, 31） and 20.0 μm （12.5, 28.2） for the first and second series of measurements, respectively. The greater amplitude of foveal choroidal thickness was associated with thickner initial foveal choroidal thickness [ 0.05 （0.03, 0.08）, P= 0.01], dominant eye 10.51 （4.02, 14.60）, P=0.04] in the multivariate linear regression. CONCLUSION： Our data show a significant diurnal variation of the choroidal thickness at fovea, at 500 μm nasal and temporal to fovea and 1500 μm nasal to fovea. Thicker initial foveal choroidal thickness and being dominant eye may influence the amplitude of foveal choroidal thickness.

Effect of thickness variations of lithium niobate on insulator waveguide on the frequency spectrum of spontaneous parametric down-conversion

We study the effect of waveguide thickness variations on the frequency spectrum of spontaneous parametric downconversion in the periodically-poled lithium niobate on insulator(LNOI)waveguide.We analyze several variation models and our simulation results show that thickness variations in several nanometers can induce distinct effects on the central peak of the spectrum,such as narrowing,broadening,and splitting.We also prove that the effects of positive and negative variations can be canceled and thus lead to a variation-robust feature and an ultra-broad bandwidth.Our study may promote the development of on-chip photon sources in the LNOI platform,as well as opens up a way to engineer photon frequency state.

ON PROBLEMS OF U-SHAPED BELLOWS WITH NONLINEAR DEFORMATION OF LARGE AXISYMMETRICAL DEFLECTION(Ⅱ)——COUNTING VARIATION OF THICKNESS DISTRIBUTION

On the basis of paper[1],assuming the logarithm of thickness at arbitrary point on a U-shaped bellows meridian is linear with the logarithm of distance between that point and axis of symmetry,perturbation solutions of the corresponding problems of large axisymmetrical deflection are given.The effects of thickness distribution variation,which result from technology factors,on stiffness of bellows are discussed.

Insight into the Electrochemical Behaviors of NCM811|SiO-Gr Pouch Battery through Thickness Variation

LiNi0.8Co0.1Mn0.1O2(NCM811)|SiOx-graphite(SiO-Gr.)battery chemistry is of intensive attention because its achievable practical energy density is approaching impressively 300 Wh Kg^(-1).However,it still suffers rapid capacity fades during repeated cycles,both chemical,electrochemical and mechanical irreversibility contribute.A comprehensive understanding behind the fading behavior of the cell chemistry is required before fully realize the benefits of this chemistry.Herein,the in-situ thickness variation is introduced as a diagnostic technique and is performed on 5-55 Ah NCM811|SiO-Gr cells.With the help of Li reference electrode and in-situ X-ray diffraction device,the correspondence between thickness variation and the electrode potential is carefully investigated.Firstly,the NCM811|SiO-Gr cell is characterized with the maximum cell thickness at around 80%state-of-charge(SOC)in the discharge process,rather than at 100%SOC.Secondly,the electrochemical behaviors during rate charge/discharge are diagnosed,and a Li platting signal is resolved from thickness variation profile at 2C.This work confirms that the thickness monitoring is a nondestructive and informative complement to conventional diagnostic techniques for failure analysis of pouch cells.

Comment on “The diurnal variation pattern of choroidal thickness in macular region of young healthy female individuals using spectral domain optical coherence tomography”

Dear Editor,We have read and reviewed the article entitled＂The diurnal variation pattern of choroidal thickness in macular region of young healthy female individuals using spectral domain optical coherence tomography＂by Zhao et al^（[1]）with great interest.

Spatiotemporal variation and freeze-thaw asymmetry of Arctic sea ice in multiple dimensions during 1979 to 2020

Arctic sea ice is broadly regarded as an indicator and amplifier of global climate change.The rapid changes in Arctic sea ice have been widely concerned.However,the spatiotemporal changes in the horizontal and vertical dimensions of Arctic sea ice and its asymmetry during the melt and freeze seasons are rarely quantified simultaneously based on multiple sources of the same long time series.In this study,the spatiotemporal variation and freeze-thaw asymmetry of Arctic sea ice were investigated from both the horizontal and vertical dimensions during 1979–2020 based on remote sensing and assimilation data.The results indicated that Arctic sea ice was declining at a remarkably high rate of–5.4×10^(4) km^(2)/a in sea ice area(SIA)and–2.2 cm/a in sea ice thickness(SIT)during 1979 to 2020,and the reduction of SIA and SIT was the largest in summer and the smallest in winter.Spatially,compared with other sub-regions,SIA showed a sharper declining trend in the Barents Sea,Kara Sea,and East Siberian Sea,while SIT presented a larger downward trend in the northern Canadian Archipelago,northern Greenland,and the East Siberian Sea.Regarding to the seasonal trend of sea ice on sub-region scale,the reduction rate of SIA exhibited an apparent spatial heterogeneity among seasons,especially in summer and winter,i.e.,the sub-regions linked to the open ocean exhibited a higher decline rate in winter;however,the other sub-regions blocked by the coastlines presented a greater decline rate in summer.For SIT,the sub-regions such as the Beaufort Sea,East Siberian Sea,Chukchi Sea,Central Arctic,and Canadian Archipelago always showed a higher downward rate in all seasons.Furthermore,a striking freeze-thaw asymmetry of Arctic sea ice was also detected.Comparing sea ice changes in different dimensions,sea ice over most regions in the Arctic showed an early retreat and rapid advance in the horizontal dimension but late melting and gradual freezing in the vertical dimension.The amount of sea ice melting and freezing was disequilibrium in the Arctic during the considered period,and the rate of sea ice melting was 0.3×10^(4) km^(2)/a and 0.01 cm/a higher than that of freezing in the horizontal and vertical dimensions,respectively.Moreover,there were notable shifts in the melting and freezing of Arctic sea ice in 1997/2003 and 2000/2004,respectively,in the horizontal/vertical dimension.

The Seasonal Variations of Aerosols over East Asia as Jointly Inferred from MODIS and OMI

Data on aerosol optical thickness(AOT) and single scattering albedo(SSA) derived from Moderate Resolution Imaging Spectrometer(MODIS) and Ozone Monitoring Instrument(OMI) measurements,respectively,are used jointly to examine the seasonal variations of aerosols over East Asia.The seasonal signals of the total AOT are well defined and nearly similar over the land and over the ocean.These findings indicate a natural cycle of aerosols that originate primarily from natural emissions. In contrast,the small-sized aerosols represented by the fine-mode AOT,which are primarily generated over the land by human activities,do not have evident seasonalscale fluctuations.A persistent maximum of aerosol loadings centered over the Sichuan basin is associated with considerable amounts of fine-mode aerosols throughout the year.Most regions exhibit a general spring maximum. During the summer,however,the aerosol loadings are the most marked over north central China.This occurrence may result from anthropogenic fine particles,such as sulfate and nitrate.Four typical regions were selected to perform a covariation analysis of the monthly gridded AOT and SSA.Over southwestern and southeastern China,if the aerosol loadings are small to moderate they are composed primarily of the highly absorptive aerosols. However,more substantial aerosol loadings probably represent less-absorptive aerosols.The opposite covariation pattern occurring over the coastal-adjacent oceans suggests that the polluted oceanic atmosphere is closely correlated with the windward terrestrial aerosols.North central China is strongly affected by dust aerosols that show moderate absorption.This finding may explain the lower variability in the SSA that accompanies increasing aerosol loadings in this region.

Variation in Wood Properties and Growth in Some Clones of <i>Populus deltoides</i>Bartr. ex Marsh

The present paper deals with within ramet radial, intra- and inter-clonal variations in the wood element’s dimensions and specific gravity of 10 clones of Populus deltoides Bartr. ex Marsh. The growth parameters namely ramet height and DBH were also considered for the study. Study material was collected from the 10 clones of Populus deltoids raised by WIMCO Plantations Ltd. at Rudrapur (Udhamsingh Nagar), India. Three clones were parent viz. G48, S7C8 (female) and G3 (male). Other clones represent hybrids of F1 generation. Inter- and intra-clonal variations were significant for all the wood traits except vessel element length for intra-clonal variations. Within ramet variations due to radial location were significant for fiber length and specific gravity with increasing trend from pith to periphery. Interaction of clone*replication was also significant for all the wood traits. Variations were significant for the DBH for the clones. Fiber length and specific gravity was significantly higher in female while wall thickness and vessel element length was in male clones (P < 0.01). Female parents (G48 and S7C8) showed higher fiber length and specific gravity than of the male parent (G3) while vessel element diameter and wall thickness was higher in male parent (G3). Fiber length was higher in offspring than the parent clones which may be the reflection of hybrid vigor for the trait. The clones of F1 offspring followed the similar patterns for the other wood traits as in the parent clones. Hierarchical cluster analysis showed that W/A 39 (male) and W 39 (female) clones of F1 generation were highly divergent than of the other clones.

NONLINEAR NATURAL FREQUENCY OF SHALLOW CONICAL SHELLS WITH VARIABLE THICKNESS

The nonlinear dynamical variation equation and compatible equation of the shallow conical shell with variable thickness are obtained by the theory of nonlinear dynamical variation equation and compatible equation of the circular thin plate with variable thickness. Assuming the thin film tension is composed of two items. The compatible equation is transformed into two independent equations. Selecting the maximum amplitude in the center of the shallow conical shells with variable thickness as the perturbation parameter, the variation equation and the differential equation are transformed into linear expression by theory of perturbation variation method. The nonlinear natural frequency of shallow conical shells with circular bottom and variable thickness under the fixed boundary conditions is solved. In the first approximate equation, the linear natural frequency of shallow conical shells with variable thickness is obtained. In the third approximate equation, the nonlinear natural frequency of it is obtained. The figures of the characteristic curves of the natural frequency varying with stationary loads, large amplitude, and variable thickness coefficient are plotted. A valuable reference is given for dynamic engineering.

Variations in wood anatomical properties and specific gravity of half sib progenies of Populus deltoides

We studied radial and inter-progeny variations in the dimen- sions of the wood elements and specific gravity of 21 half sib progenies of Populus deltoides Bartr. ex Marsh. The female parents of half sib progenies were G48 and $7C13 clones. Variance ratio （F） test indicated that inter-progeny variations in the dimensions of wood elements and specific gravity were significant for all wood traits while variations were significant for radial location for specific gravity only. Hierarchical clus- ter analysis was done by Squared Euclidean Distance for all of 21 proge- nies considering six wood traits. 21 progenies were grouped into 4 clus- ters. Cluster 1 was the largest cluster with 11 progenies, whereas cluster 3 had only one progeny. Selected progenies in clusters 3 （progeny 155, male） and 4 （progeny 108, 196, both female） were highly divergent from the other progenies so they were used in combinations as parents of hybrids to develop new clones with desired characters. Progeny 155 showed higher growth, fiber dimensions, and specific gravity, thus, should be used for the development of new clones.

Simulated response of the active layer thickness of permafrost to climate change

The active layer thickness(ALT)in permafrost regions,which affects water and energy exchange,is a key variable for assessing hydrological processes,cold-region engineering,and climate change.In this study,the authors analyzed the variation trends and relative changes of simulated ALTs using the Chinese Academy of Sciences Land Surface Model(CAS-LSM)and the Chinese Academy of Sciences Flexible Global Ocean-Atmosphere-Land System Model,gridpoint version 3(CAS-FGOALS-g3).Firstly,the simulated ALTs produced by CAS-LSM were shown to be reasonable by comparing them with Circumpolar Active Layer Monitoring observations.Then,the authors simulated the ALTs from 1979 to 2014,and their relative changes across the entire Northern Hemisphere from 2015 to 2100.It is shown that the ALTs have an increasing trend.From 1979 to 2014,the average ALTs and their variation trends over all permafrost regions were 1.08 m and 0.33 cm yr-1,respectively.The relative changes of the ALTs ranged from 1%to 58%,and the average relative change was 10.9%.The variation trends of the ALTs were basically consistent with the variation trends of the 2-m air temperature.By 2100,the relative changes of ALTs are predicted to be 10.3%,14.6%,30.1%,and 51%,respectively,under the four considered hypothetical climate scenarios(SSP-2.6,SSP2-4.5,SSP3-7.0,and SSP5-8.5).This study indicates that climate change has a substantial impact on ALTs,and our results can help in understanding the responses of the ALTs of permafrost due to climate change.

Failure of Semi-infinite Beams of Variable Thickness and Curvature on Elastic Foundation under Contact Loading

In early winter it is usual, in cold regions, that ice features approach offshore structures, like offshore platforms, impacting them, in a slow process of constant deformation build up. Interaction follows, in many cases, up to the point where ice-failure caused by bending fracture takes place. This supposes very large contact forces that the structure has to resist. Therefore, quantification of these efforts is of vital importance to the structural design of platforms. In several designs, these platforms are constructed with inclined walls so as to cause ice to fail in a flex-compression mode. In such a case the ice feature is analyzed as a beam constituted of a linear elastic material in brittle state with constant ice thickness. The simplification renders the problem solvable in a close form. However, this hypothesis goes against field observations. Marine currents action, wind and the sequence of contacts among features lead to thickness variations. Here this factor is addressed in the construction of a model, for harmonic forms of variation of thickness profile, and the accompanying curvature variations, whose solution determines field variables used to address the failure question. Due to the deformation dependency of the loading, a numerical scheme for the two-point boundary value problem in the semi-infinite space is developed. Failure pressures are computed based on a Rankine locus of failure. Variations of the order of 20% in the failure loads, as compared to the uniform beam model, are observed.

A variational principle analysis of surface acoustic waves propagating under periodic metal grating with finite thickness

A theoretical method is presented,which analyzes properties of surface acoustic waves propagating on metallic gratings with finite thickness by combining finite element method with variational principle on surface acoustic waves propagating on periodic metal gratings. Based on D.P.Chen and Haus theory,a finite element method is used to investigate the effects of metallic gratings upon the propagation of surface acoustic waves.The coupling-of-modes parameters contributed by mechanical loading are expressed by the matrix derived from the finite element method.Consequently D.P.Chen and Haus theory can also be applied to analyze the properties of surface acoustic waves propagating on metallic gratings with finite thickness and arbitrary shape.Finally,the characteristics of surface acoustic waves propagating under gold and aluminum or silver gratings on a few piezoelectric crystals are studied.Numerical results of the coupling-of-modes parameters of the surface acoustic waves are obtained.

Genetic evidence for facial variation being a composite phenotype of cranial variation and facial soft tissue thickness

Facial and cranial variation represent a multidimensional set of highly correlated and heritable phenotypes.Little is known about the genetic basis explaining this correlation.We develop a software package ALo SFL for simultaneous localization of facial and cranial landmarks from head computed tomography(CT)images,apply it in the analysis of head CT images of 777 Han Chinese women,and obtain a set of phenotypes representing variation in face,skull and facial soft tissue thickness(FSTT).Association analysis of 301 single nucleotide polymorphisms(SNPs)from 191 distinct genomic loci previously associated with facial variation reveals an unexpected larger number of loci showing significant associations(P<1e-3)with cranial phenotypes than expected under the null(O/E=3.39),suggesting facial and cranial phenotypes share a substantial proportion of genetic components.Adding FSTT to a SNP-only model shows a large impact in explaining facial variance.A gene ontology analysis reveals that bone morphogenesis and osteoblast differentiation likely underlie our cranial-significant findings.Overall,this study simultaneously investigates the genetic effects on both facial and cranial variation of the same sample,supporting that facial variation is a composite phenotype of cranial variation and FSTT.

THEORY OF THICK-WALLED SHELLS AND ITS APPLICATION IN CYLINDRICAL SHELL

In this paper, a theory of thick-walled shells is established by means of Hellinger-Reissner's variational principle, with displacement and stress assumptions. The displacements are expanded into power series of the thickness coordinate. Only the first four and the first three terms are used for the displacements parallel and normal to the middle surface respectively. The normal extruding and transverse shear stresses are assumed to be cubic polynomials and to satisfy the boundary stress conditions on the outer and inner surfaces of the shell. The governing equations and boundary conditions are derived by means of variational principle. As an example, a thick-walled cylindrical shell is disscussed with the theory proposed. Furthermore, a photoelastic experiment has been carried out, and the results are in fair agreement with the computations.