Modified non-rectangular hyperbola equation with plant height for photosynthetic light-response curves of Potentilla anserina and Elymus nutans at various growth phases in the Heihe River Basin, Northwest China

The non-rectangular hyperbola(NRH)equation is the most popular method that plots the photosynthetic light-response(PLR)curve and helps to identify plant photosynthetic capability.However,the PLR curve can't be plotted well by the NRH equation at different plant growth phases due to the variations of plant development.Recently,plant physiological parameters have been considered into the NRH equation to establish the modified NRH equation,but plant height(H),an important parameter in plant growth phases,is not taken into account.In this study,H was incorporated into the NRH equation to establish the modified NRH equation,which could be used to estimate photosynthetic capability of herbage at different growth phases.To explore photosynthetic capability of herbage,we selected the dominant herbage species Potentilla anserina L.and Elymus nutans Griseb.in the Heihe River Basin,Northwest China as the research materials.Totally,twenty-four PLR curves and H at different growth phases were measured during the growing season in 2016.Results showed that the maximum net photosynthetic rate and the initial slope of PLR curve linearly increased with H.The modified NRH equation,which is established by introducing H and an H-based adjustment factor into the NRH equation,described better the PLR curves of P.anserina and E.nutans than the original ones.The results may provide an effective method to estimate the net primary productivity of grasslands in the study area.

MODIFIABLE QUARTIC AND QUINTIC CURVES WITH SHAPE-PARAMETERS

This paper presents a method for creating modificable quartic and quintic curves with shape parameters. The curves can achieve C 2 even C 3 continuity and unify both interpolation and approximation to the control points without solving a system of equations or inserting additional control points. They have the local properties like the cubic B spline. Besides, the quintic curve would be able globally to tend the control polygon.

Restoring-force model of modified RAC columns with silica fume and hybrid fiber

In order to establish a restoring-force model for modified concrete columns with recycled aggregates concrete(RAC), cyclic loading tests were carried out on five concretes with RAC columns and ordinary concrete frame columns under the combined influence with different admixtures and admixtures ratios(silica fume and hybrid fiber). The expressions for characteristic nodes of the skeleton curve were given by the analysis and numerical regression of the test results. In addition, the hysteretic rules of the restoring-force model and the expression for unloading stiffness were presented. Finally, we summed up the complete calculation method of the hysteretic restoring force, whose results were in good agreement with experiment. The results demonstrated that the proposed model could simulate and reflect the corresponding hysteretic behaviors, and the calculation method can provide the theoretical basis for the engineering application.

Mechanical Properties of Sea Water Sea Sand Coral Concrete Modified with Different Cement and Fiber Types

The mechanical properties of modified sea water sea sand coral concrete(SWSSCC)under axial compression were experimentally studied.Two different parameters were considered in this test:types of cement and fiber.An experimental campaign was developed involving uniaxial compression tests and the use of digital image correlation(DIC)method to analyze the strain distribution and crack propagation of specimen.Test results indicated that the compressive strength and elastic modulus of SWSSCC were improved by adding stainless steel fibers(SSF),while polypropylene fibers(PF)enhanced the SWSSCC peak deformation.It was found that the elastic modulus and strength of SWSSCC using ordinary Portland cement(OPC)were higher compared to specimen with low alkalinity sulphoaluminate cement(LAS).Typical strain distribution changed with the variation of fiber types.The propagation and characteristics of cracks in SWSSCC containing PF were similar to those of cracks in SWSSCC.However,the propagation of cracks and the development of plastic deformation in SWSSCC were effectively hindered by adopting SSF.Finally,an analytical stress-strain expression of specimen considering the influences of fibers was established.The obtained results would provide a basis for the application of SWSSCC.

Prediction of forming limit curve for pure titanium sheet

Commercially pure titanium（CP Ti） has been actively used in the plate heat exchanger due to its light weight, high specific strength, and excellent corrosion resistance. However, researches for the plastic deformation characteristics and press formability of the CP Ti sheet are not much in comparison with automotive steels and aluminum alloys. The mechanical properties and hardening behavior evaluated in stress-strain relation of the CP Ti sheet are clarified in relation with press formability. The flow curve denoting true stress-true strain relation for CP Ti sheet is fitted well by the Kim-Tuan hardening equation rather than Voce and Swift models. The forming limit curve（FLC） of CP Ti sheet as a criterion for press formability was experimentally evaluated by punch stretching test and analytically predicted via Hora＇s modified maximum force criterion. The predicted FLC by adopting Kim-Tuan hardening model and appropriate yield function shows good correlation with the experimental results of punch stretching test.

APPLICATION OF THE CLUSTERING METHOD IN ANALYSING SHALLOW WATER MASSES AND MODIFIED WATER MASSES IN THE HUANGHAI SEA AND EAST CHINA SEA

The idea of modified water masses is introduced and a cluster analysis is used for determining the boundary of modified water masses and its variety in the shallow water area of the Huanghai Sea (Yellow Sea) and the East China Sea. According to the specified standards to make the cluster, we have determined the number and boundary of the water masses and the mixed zones.The results obtained by the cluster method show that there are eight modified water masses in this area. According to the relative index of temperature and salinity,the modified water masses are divided into nine different characteristic parts. The water, masses may also be divided into three salinity types. On the TS-Diagram, the points concerning temperature and safinity of different modified mater masses are distributed around a curve, from which the characteristics of gradual modification may be embodied. The variation ranges of different modified water masses are all large, explaining the intensive modification of water masses in

APPROXIMATE VIBRATION ANALYSIS OF LAMINATED CURVED PANEL USING HIGHER-ORDER SHEAR DEFORMATION THEORY

An approximate analysis for free vibration of a laminated curved panel(shell)with four edges simply supported(SS2),is presented in this paper.The transverse shear deformation is considered by using a higher-order shear deformation theory.For solving the highly coupled partial differential governing equations and associated boundary conditions,a set of solution functions in the form of double trigonometric Fourier series,which are required to satisfy the geometry part of the considered boundary conditions,is assumed in advance.By applying the Galerkin procedure both to the governing equations and to the natural boundary conditions not satisfied by the assumed solution functions,an approximate solution,capable of providing a reliable prediction for the global response of the panel,is obtained.Numerical results of antisymmetric angle-ply as well as symmetric cross-ply and angle-ply laminated curved panels are presented and discussed.

EFFECT OF SPECIMEN SIZE ON J_R RESISTANCE CURVE

The effect of specimen thinkness on JR resistance curve has been investigated using low and middle strength steels. As the J dominance regime is reached, the initial J-integral values, J(i), are definite even if the elastic component Ji(e) and plastic component Ji(p)vary with the thinkness of specimen. The wider the specimen width, the larger the Ji(e)/Ji and the smaller the Ji(p)/Ji. The crack propagation resistance, dJR/da and dJp/da, decreases, while dJe/da increases linearly with increasing specimen thinness.Based on the above experimental results, an empirical formula dJ/da = α+β. B is given, which can be used to evaluate the safety of practical structural components.A modified J-integral is presented, upon which a new view is Put forward that the increase in crack growth resistance is induced mainly by the increase in the plastic J-integral component with the crack propagation,

A modified exponential model for reported death toll during earthquakes

Reliable earthquake death toll estimate can provide valuable references for disaster relief headquarters and civil administration departments to make arrangement and deployment plan during post-earthquake relief work, thus increasing the efficiency of the relief work to a certain extent. In this study, we acquired the death toll data of Wenchuan earth- quake, fitted the data using modified exponential curve and compared the result with that of the exponential function. Experimental verification with Chi-Chi earthquake and Kobe earthquake data shows that the fitted result by modified exponential curve is more satisfactory. The final death toll resulting from future destructive earthquakes can be estimated by the acquired fitting function.

Modified couple stress and thickness-stretching included formulation of a sandwich micro shell subjected to electro-magnetic load resting on elastic foundation

This paper studies electromagnetoelastic static investigation of a sandwich doubly curved microshell subjected to multi-field loading based on a new thickness stretching included refined higher order shear/normal deformable model.Modified-couple-stress-theory(MCST)is used for accounting small-scaledependency.The numerical results are derived using an analytical method.The effect of small scale parameter in micro scale,initial electric and magnetic potentials and foundation parameters is studied on the electromagnetoelastic bending results.It is confirmed an enhancing in stiffness of small scale shell with an increase in micro length scale parameter.

A Model of Modified Newtonian Gravity Alternative to MOND, Consistent with the Properties of Spiral Galaxies and Compatible with Extragalactic Dark Matter

A new model of the modified Newtonian gravity called Compacted & Collapsing Gravity (CCG) is proposed. Similar to the Milgrom’s MOND, it allows explaining the flattening of rotation curve in spiral galaxies, thus eliminates the need for dark matter at this level. However, in contrast to MOND, it puts a distinct limit on effective gravity;thereby constraints the sizes of single galaxies in connection to their masses, which complies with observations. In the bigger than single galaxies structures such as galaxy clusters, CCG rather complements than replaces interpretations of the observational data based on dark matter. Besides, the new model provides a plausible explanation to the hierarchical structure of the universe.

STUDY ON THE PROPERTIES OF ACID-MODIFIED MULTIFUNCTION COPOLYESTER FIBRE

Applying conventional analytical methods,the following results have been found:the satura-tion value of acid--modified multifunction copolyest fibre( acid-modified polyester fibre)is1.74,then this kind of fibre is good for being dyed medium and light colours with cationicdyes;its level of erystalization is lower than of PET fibre;the third monomer(SIPM)con-tent in the fibre will be reduced by about 8% by the "alkali treatment"in dyeing and finishingprocess:through measuring and analysing the dye-up-take curves of time and temperature ofdyeing the fibre with cationic dyes,we indicate the key factors in dyeing are the 100℃ dyeingtemperature and the time for heat preservation;moveover,adding sodium sulphate will help leveldyeing but lower the dye-uptake.

Improved modified moving average analysis of T-wave alternans using least squares-based curve fitting method

T-wave alternans （TWA） in surface electrocardiograph （ECG） signal is considered a marker of abnormal ventricular function which may be associated with ventricular tachy- cardia. Several methods have been developed in recent years to evaluate the important feature. One such method is known as modified moving average （MMA） analysis, which performs well for different levels of TWA, but it is sensitive to the noise in T-waves. In this paper we propose an improved MMA algorithm, which adds a stage of T-wave curve fitting for the MMA method before intermediate averaging. The curve fitting is performed by means of least square method technique. Our assessment study demon- strates the improved performance.

Interpretation of Rotation Curves of Spiral Galaxies in Modified Teleparallel Gravity

There is a significant difference between the calculation based on the theory of general relativity and observation of rotation curves of spiral galaxies. To describe this discrepancy, two distinct theories have been proposed so far： existence of dark matter and modification of underlying gravitational theory. In the absence of dark matter, it is assumed that the theory of general relativity on galactic scales needs to be modified. This letter is devoted to explaining this difference in a modified teleparMIeI gravity. We show that modified teleparallel gravity favors flatness of rotation curves of spiral galaxies much in the same way as observation shows.

Graphical method based on modified maximum force criterion to indicate forming limit curves of 22MnB5 boron steel sheets at elevated temperatures

A new approach for predicting forming limit curves(FLCs)at elevated temperatures was proposed herein.FLCs are often used to predict failure and determine the optimal forming parameters of automotive parts.First,a graphical method based on a modified maximum force criterion was applied to estimate the FLCs of 22MnB5 boron steel sheets at room temperature using various hardening laws.Subsequently,the predicted FLC data at room temperature were compared with corresponding data obtained from Nakazima's tests to obtain the best prediction.To estimate the FLC at elevated temperatures,tensile tests were conducted at various temperatures to determine the ratios of equivalent fracture strains between the corresponding elevated temperatures and room temperature.FLCs at elevated temperatures could be established based on obtained ratios.However,the predicted FLCs at elevated temperatures did not agree well with the corresponding FLC experimental data of Zhou et al.A new method was proposed herein to improve the prediction of FLCs at elevated temperatures.An FLC calculated at room tem-perature was utilized to predict the failure of Nakazima's samples via finite element simulation.Based on the simulation results at room temperature,the mathematical relationships between the equivalent ductile fracture strain versus stress triaxiality and strain ratio were established and then combined with ratios between elevated and room temperatures to calculate the FLCs at different temperatures.The predicted FLCs at elevated temperatures agree well with the corresponding experimental FLC data.

复合多聚磷酸改性沥青混合料动态力学性能

为研究多聚磷酸(polyphosphoric acid,PPA)+SBS复合改性沥青混合料的动态力学性能,采用单轴压缩动态模量试验,分析温度和频率对动态模量和相位角的影响,并基于改进Havriliak-Negam(i HN)模型构建动态模量和相位角主曲线,同时与SBS改性沥青混合料相对比。结果表明:2种沥青混合料动态模量和相位角随温度和频率的变化呈现相同的趋势,HN模型可准确拟合2种沥青混合料的动态模量和相位角主曲线。相较于SBS改性沥青混合料,PPA+SBS复合改性沥青混合料的相位角在-10、20、50℃时均降低,而动态模量在-10℃时降低,20℃时变化较小,50℃时增加;较宽频域范围内,PPA+SBS复合改性沥青混合料在高温低频下动态模量变大,相位角变小,在低温高频下动态模量变小,相位角变化不大;PPA+SBS复合改性沥青混合料具有更优的动态力学性能。

改良雨水生物滞留系统截留微塑料效果及影响因素探究

选取聚乙烯(PE,疏水)和聚苯乙烯乳胶微球(PS,亲水)两种使用广泛且在水环境中频繁检出的微塑料为代表,对基质为90%砂土+10%给水厂污泥的雨水生物滞留系统在不同水力停留时间、离子强度、pH值和阳离子类型条件下截留微塑料的效果进行了研究。结果表明,当进水中两种微塑料的丰度分别为5.0×10^(4),5.3×10^(4)个/L、HRT为10 min时,微塑料在改良雨水生物滞留系统中开始穿透及完全穿透时间较传统雨水生物滞留系统均明显后移。在改良雨水生物滞留系统中,HRT由10 min提升至30 min后,聚乙烯开始穿透从90 min(9 FVs)后移至360 min(12 FVs),聚苯乙烯乳胶微球开始穿透从40 min(4 FVs)后移至240 min(8 FVs);高离子强度时(50.0 mmol/L)系统对微塑料的截留能力更强;pH及阳离子类型对微塑料的截留效果无明显影响。

收敛约束法在挤压性围岩隧道中的应用

由于挤压性围岩隧道围岩性质与应力环境的特殊性,其围岩特征曲线与常规隧道有明显差异。为研究挤压性围岩隧道围岩-支护相互作用关系,考虑支护效应修正围岩特征曲线,研究不同变形等级对修正围岩特征曲线的影响规律,优化挤压性围岩双线铁路隧道初期支护。研究结果表明,毛洞状态下,受双线隧道断面应力集中影响,拱脚和墙脚为安全控制位置;随着变形等级和侧压力系数增加,支护特征曲线与修正围岩特征曲线不再相交;Ⅰ、Ⅱ级变形采用单层支护可满足安全要求,锚杆只需布置在拱部和边墙位置,Ⅱ级及以上变形锚杆需要全环布置;Ⅳ级变形在采用双层支护的同时,需考虑改善洞室形状、超前加固等措施。

基于双默克尔树区块结构的交易粒度联盟链修改方案

随着区块链技术的蓬勃发展,以区块链为底层架构的信息系统已应用于包括数字货币、供应链等众多领域。在监管和实际应用双重需求的驱动下,可修改区块链技术因能够进行安全且权责分明的数据治理而成为当前研究的热点。然而,目前的修改方案中仍然存在修改权限过度中心化、修改效率不高等问题。针对上述问题,提出了一种交易粒度联盟链账本修改方案,构建了双默克尔树区块结构,利用椭圆曲线加密和迪菲-赫尔曼秘钥交换技术将变色龙哈希陷门信息(即变色龙哈希私钥)加密存储在区块中,降低密钥分发的系统通信开销。在此基础之上,通过默克尔树将修改权与用户绑定,修改提案受权限节点投票审查,有效防止了修改权的滥用,进一步提高了区块链系统的监管问责能力。实验表明,该联盟链账本修改方案的算法执行速率整体达到毫秒级,并大幅降低了链上数据修改操作的额外开销。

超高性能海水海砂混凝土单轴受压应力-应变关系

为研究超高性能海水海砂混凝土(Ultra-High Performance Seawater Sea-sand Concrete,UHPSSC)轴压应力-应变关系,探究钢纤维体积掺量对UHPSSC轴压力学性能和轴压应力-应变全曲线的影响,使用Instron 1346万能材料试验机测得UHPSSC应力-应变全曲线,借助Pycharm曲线拟合程序与已有混凝土应力-应变全曲线模型进行拟合与修正.结果表明:钢纤维掺量越高,轴压作用下UHPSSC的破坏程度越小,抗压强度和峰值应变也随之增加;已有模型拟合的UHPSSC应力-应变全曲线上升段与试验曲线比较相近,下降段后期差距较大;通过修正下降段形状参数,得到了更适用于描述UHPSSC应力-应变全曲线的修正模型,并验证该修正模型的适用范围.