Mechanical Properties and Stress Strain Relationship Models for Bamboo Scrimber

In order to investigate the basic mechanical properties and stress strain relationship model for bamboo scrimber manufactured based on a new technique,a large quantities of experiments have been carried out.Based on the analysis of the test results,the following conclusions can be drawn.Two main typical failure modes were classified for bamboo scrimber specimens both under tension parallel to grain and tension perpendicular to grain.Brittle failure happened for all tensile tests.The slope values for the elastic stages have bigger discreteness compared with those for the specimens under tensile parallel to grain.The failure modes for bamboo scrimber specimens under compression parallel to grain could be divided into four.Only one main failure mode happened both for the bending specimens and the shear specimens.With the COV values of 28.64 and 25.72 respectively,the values for the strength and elastic modulus under tensile perpendicular to grain have the largest discreteness for bamboo scrimber.From the point of CHV values,the relationship among the mechanical parameters for bamboo scrimber were proposed based on the test results.Compared with other green building materials,bamboo scrimber manufactured based on a new technique has better mechanical performance and could be used in construction area.Three stress strain relationship models which are four-linear model,quadratic function model,and cubic function model were proposed for bamboo scrimber specimens manufactured based on a new technique.The latter two models gives better prediction for stress strain relationship in elastic plastic stage.

Precipitation-Surface Temperature Relationship in the IPCC CMIP5 Models

Precipitation and surface temperature are two important quantities whose variations are closely related through various physical processes. In the present study, we evaluated the precipitation-surface temperature （P-T） relationship in 17 climate models involved in the Coupled Model Intercomparison Project Phase 5 （CMIP5） for the IPCC Assessment Report version 5. Most models performed reasonably well at simulat- ing the large-scale features of the P-T correlation distribution. Based on the pattern correlation of the P-T correlation distribution, the models performed better in November-December-January-February-March （NDJFM） than in May-June-July-August-September （MJJAS） except for the mid-latitudes of the North- ern Hemisphere, and the performance was generally better over the land than over the ocean. Seasonal dependence was more obvious over the land than over the ocean and was more obvious over the mid- and high-latitudes than over the tropics. All of the models appear to have had difficulty capturing the P-T correlation distribution over the mid-latitudes of the Southern Hemisphere in MJJAS. The spatial variabil- ity of the P-T correlation in the models was overestimated compared to observations. This overestimation tended to be larger over the land than over the ocean and larger over the mid- and high-latitudes than over the tropics. Based on analyses of selected model ensemble simulations, the spread of the P-T correlation among the ensemble members appears to have been small. While the performance in the P-T correlation provides a general direction for future improvement of climate models, the specific reasons for the discrep- ancies between models and observations remain to be revealed with detailed and comprehensive evaluations in various aspects.

Modeling of the height–diameter relationship using an allometric equation model:a case study of stands of Phyllostachys edulis

Understanding the relationship between tree height （H） and diameter at breast height （D） is vital to forest design, monitoring and biomass estimation. We developed an allometric equation model and tested its applicability for unevenly aged stands of moso bamboo forest at a regional scale. Field data were collected for 21 plots. Based on these data, we identified two strong power relationships： a corre- lation between the mean bamboo height （Hm） and the upper mean H （Hu）, and a correlation between the mean D （Din） and the upper mean D （Du）. Simulation results derived from the aUometric equation model were in good agreement with observed culms derived from the field data for the 21 stands, with a root-mean-square error and relative root-mean-square error of 1.40 m and 13.41%, respectively. These results demonstrate that the allometric equation model had a strong predictive power in the unevenly aged stands at a regional scale. In addition, the estimated average height-diameter （H-D） model for South Anhui Province was used to predict H for the same type of bamboo in Hunan Province based on the measured D, and the results were highly similar. The allometric equation model has multiple uses at the regional scale, including the evaluation of the variation in the H- D relationship among regions. The model describes the average H-D relationship without considering the effects caused by variation in site conditions, tree density and other factors.

Numerical Method for Modeling the Constitutive Relationship of Sand under Different Stress Paths

A numerical method was used in order to establish the constitutive relationship of sands under different stress paths, Firstly, based on the numerical method modeling the constitutive law of sands, the elastoplastic constitutive relationship of sand was established for three paths： the constant proportion of principle stress path, the conventional triaxial compression （CTC） path, and the p=constant （TC） path. The yield lines of plastic volumetric strain and plastic generalized shear strain were given. Through visualization, the three dimensional surface of the stress-strain relationship in the whole stress field （p, q） obtained under the three paths was plotted. Also, by comparing the stress-strain surfaces and yield locus of the three stress paths, the differences were found to be obvious, which demonstrates that the influence of the stress paths on constitutive law was not neglected. The numerical modeling method overcame the difficulty of finding an analytical expression for plastic potential. The results simulated the experimental data with an accuracy of 90% on average, so the constitutive model established in this paper provides an effective constitutive equation for this kind of engineering, reflecting the effect of practical stress paths that occur in sands.

Seismic ground motion relationships in southern China based on stochastic finite-fault model

The characteristics of seismic ground motions in southern China are difficult to determine statistically due to a lack of strong ground motion data.In this study,a stochastic finite-fault ground motion model was adopted to simulate the seismic ground motions at bedrock for southern China,based on parameters derived from small and medium earthquakes that have occurred in the region.From these,the response spectra was estimated.A set of ground motion attenuation relationships was then developed based on simulated peak ground motions and response spectral parameters through regression,which would be applicable for use in engineering practice.Through comparisons,it was demonstrated that the proposed ground motion relationships are generally consistent with those obtained from other reported ground motion attenuation models for southern China.

GIS-Based Urbanization Prediction Model Considering Neighborhood Relationship of the Unit of the “Block” in the Outskirts of Metropolitan Area

On the outskirts of the metropolitan areas in Japan, the rapid development of urban areas and the improvement in transportation networks have brought various land use problems in their wake, including urban diffusion and the phenomenon of urban sprawl. There is a strong need for accurate predictions of land-use change and future urbanization, as well as investigation of the appropriateness of present land use controls and the land use controls that will be required in the future. This study took as its object the outskirts of the Keihanshin (Kyoto-Osaka-Kobe) Metropolitan Area, the second largest conurbation in Japan after the Tokyo Metropolitan Area, and used the digital maps and spatial analysis offered by GIS. It aimed to: 1) describe the characteristics of land use controls, land use and urbanization;2) develop an urbanization prediction model that considers the neighboring relationship of neighboring areas on a 100 m mesh unit;3) apply this model to the study area and verify its validity regarding the conditions of present land use;4) compare urbanization prediction results by this model with the present land use controls;and 5) make predictions for future urbanization and propose remedial measures for future land use controls.

Relationship between rock uniaxial compressive strength and digital core drilling parameters and its forecast method

The rock uniaxial compressive strength(UCS)is the basic parameter for support designs in underground engineering.In particular,the rock UCS should be obtained rapidly for underground engineering with complex geological conditions,such as soft rock,fracture areas,and high stress,to adjust the excavation and support plan and ensure construction safety.To solve the problem of obtaining real-time rock UCS at engineering sites,a rock UCS forecast idea is proposed using digital core drilling.The digital core drilling tests and uniaxial compression tests are performed based on the developed rock mass digital drilling system.The results indicate that the drilling parameters are highly responsive to the rock UCS.Based on the cutting and fracture characteristics of the rock digital core drilling,the mechanical analysis of rock cutting provides the digital core drilling strength,and a quantitative relationship model(CDP-UCS model)for the digital core drilling parameters and rock UCS is established.Thus,the digital core drilling-based rock UCS forecast method is proposed to provide a theoretical basis for continuous and quick testing of the surrounding rock UCS.

An LCOR model for suppressing cascading failure in weighted complex networks

Based on the relationship between capacity and load, cascading failure on weighted complex networks is investigated, and a load-capacity optimal relationship （LCOR） model is proposed in this paper. Compared with three other kinds of load- capacity linear or non-linear relationship models in model networks as well as a number of real-world weighted networks including the railway network, the airports network and the metro network, the LCOR model is shown to have the best robustness against cascading failure with less cost. Furthermore, theoretical analysis and computational method of its cost threshold are provided to validate the effectiveness of the LCOR model. The results show that the LCOR model is effective for designing real-world networks with high robustness and less cost against cascading failure.

土壤中金属元素生态安全阈值预测模型的构建

通过文献收集了31种中国土壤中8个元素对5个物种和3个微生物过程的616个毒理学数据,尝试构建土壤中数据有限元素毒性预测的新模型—定量离子特征活性关系(s-QICAR)模型.首先基于土壤性质归一化方法获得酸性、中性、碱性3种土壤情景下8个元素对5个物种和3个微生物的毒性值(logEC10;1.42~3.35),在此基础上分析了元素23个结构特征参数与对应生物毒性值的关系,并利用元素共价半径(CR)建立了24个s-QICAR模型(R^(2)=0.70~0.98;P=0.001~0.023).进一步利用s-QICAR预测了V、As、Se和Sn对8个物种的logEC_(10)(1.44~3.20),结合物种敏感性分布曲线计算了3种情景下这4种元素保护95%生物的HC5值.经过校正,4种元素在酸性、中性、碱性土壤情景下的预测无效应浓度分别为V:13,16,17mg/kg;As:10,13,15mg/kg;Se:4.9,7.2,8.4mg/kg;Sn:42,44,45mg/kg,进而绘制了这4种元素的生态风险阈值地图.本研究建立了一种适用于中国土壤元素生态风险的新方法,为土壤环境风险评估和管理提供科学依据.

拉考沙胺国外儿童群体药动学模型外部验证和精准用药

目的采用真实世界收集的病例数据验证国外报道的拉考沙胺儿童群体药动学(PPK)模型的预测性能,同时分析暴露-效应关系并模拟优化给药方案。方法收集64例年龄4~13.42岁癫痫患儿口服拉考沙胺达稳态后的血药浓度数据和临床资料,通过拟合优度图和直观预测检验考察国外模型的预测准确性。分析拉考沙胺给药日剂量或谷浓度与临床疗效的关系,并基于药动学参数采用蒙特卡罗模拟评价和筛选拉考沙胺用于不同体质量分层及联合用药情况下最佳给药剂量方案。结果外部验证结果显示国外儿童PPK模型的预测准确性较好。基于模型采用贝叶斯法得到拉考沙胺单药治疗癫痫儿童的药动学参数分别为:吸收速率常数(k a)=(2.43±0.04)h^(-1),表观分布容积(V d/F)=(22.69±6.00)L,清除率(CL/F)=(1.25±0.27)L·h^(-1),半衰期(t 1/2)=(12.74±2.40)h。临床有效病例日剂量5%~95%分位数分布区间为2.5~6.3 mg·kg^(-1)·d^(-1),谷浓度5%~95%分位数分布区间为1.9~6.7 mg·L^(-1)。模拟结果显示,按该研究推荐的拉考沙胺优化给药方案可提高药物浓度的达标概率,保障治疗的有效性和耐受性。结论该研究验证了拉考沙胺国外儿童PPK模型的预测性能,并基于此模型模拟了优化给药方案,可为临床医生个体化合理用药提供参考。

Parameter Fitting of Seismic Intensity Attenuation Model in Xinjiang

By using the existing historical earthquake investigation data in Xinjiang,this paper obtained the envelope curves of isoseismal maps of 103 destructive earthquakes occurring from 1716 to 2010 after digitization of the data. The author summarized the seismic intensity attenuation laws in the Xinjiang region with the multiple regression fitting method. The intensity attenuation function of the elliptical model was provided and the fitting results in different periods and areas were compared. Finally, the intensity attenuation relationship in the Xinjiang region was obtained by the method of constraining the start and end of the attenuation curves.

木质素-稻草改良土的力学特性与修正Duncan-Chang模型

木质素具有胶结土体的作用,稻草纤维也具备提高土体抗剪强度的能力,而采用木质素和稻草共同改良红黏土的研究相对较少。本文通过固结不排水三轴试验,获得了木质素-稻草改良土在不同围压和不同木质素掺量下的应力-应变曲线,并据此研究该改良土的力学特性;同时通过建立修正Duncan-Chang模型,来分析木质素掺量对模型参数的影响。研究结果表明:改良土主应力差随木质素掺量的增加先增大后减小,当木质素的掺量为0.7%时,其到达最大值;改良土初始变形模量Ei、极限偏应力(σ1-σ3)ult、黏聚力c、内摩擦角φ及参数K均随木质素掺量的增加先增大后减小,参数n随木质素掺量的增加而增大,而破坏比Rf受木质素掺量的影响较小。

A Comparative Study of the Jerome Model and the Horace Model

This paper will try to compare the Jerome model with the Horace model to look into advantages, shortages and relationship be-tween them. It mainly discusses the important roles of the Jerome model and the Horace model in turning Chinese from their translation ef-fects. The present article comes to a conclusion that they are opposite, related, complementary, melting and permeating. And it gives us anidea that we should neither praise nor censure either of them, and we should adopt a correct method according to the concrete conditions toachieve a perfect translation effect.

不同时间尺度森林群落多样性-稳定性关系

森林群落稳定性是体现森林面对干扰抵抗能力的重要指标,已知森林生物量稳定性会受到多样性、物种异步性和优势物种稳定性的影响,然而,关于这些变量在不同时间尺度下的相对重要性的相关研究较少,本文旨在探索不同时间尺度下森林群落稳定性影响因素。基于吉林省金沟岭林场的110块固定样地数据,本文利用相关性分析研究不同时间尺度下多样性、优势物种稳定性、物种异步性和森林群落生物量稳定性的相关关系是否一致,接着采用结构方程模型计算直接效应和总效应。结果表明,物种丰富度、胸径变异系数、物种异步性与稳定性总是呈显著正相关关系。随着时间尺度的增大,物种异步性的直接效应由0.44增长为0.63,总相对效应由36.87%增长为45.57%,物种异步性一直是影响森林生物量时间稳定性的最重要因素。本研究得出影响群落稳定性的最重要因素,有助于更好地理解森林生态系统多样性-稳定性关系的机制,然而多样性-稳定性关系及其机制是复杂的,未来仍需要选择不同多样性指标进行深入研究。

面向STEP模型装配特征自动提取的装配信息模型构建

装配信息建模是数字化装配、智能化装配的基础,然而人工交互建模效率低下且易发生装配特征识别和装配特征配合的错误,难以满足复杂机械系统的精确建模。基于三维装配体模型隐含的装配工艺信息,以STEP模型文件为输入,研究了面向几何信息的装配特征自动提取与配合关系识别算法。进而针对装配集成信息模型的构建,从装配精度模型和装配序列规划角度提出了信息推理算法。最后基于开发的系统,通过装配实例信息模型构建证明了所提算法的有效性。

旅游产业效率与区域经济发展异速关系时空特征及机理分析——以湖南省为例

旅游产业效率是旅游业提质增效的关键因素,是由粗放型向高质量发展转变的着力点;旅游产业效率与区域经济异速关系分析是深层次解析城市产业结构转型的重要依据。选择湖南省14个市州为研究对象,采用熵值法和DEAMalmquist模型对湖南省2006—2019年间旅游产业效率进行测度,并进一步采用空间变差函数和异速增长模型分析旅游产业效率与区域经济发展的异速增长情况。结果表明:(1)湖南省旅游产业效率存在差异,总体上呈现上升趋势,但与经济增速相比,效率增长略慢。以第二产业为主的其他行业的发展速度超过了旅游业,导致经济增速高于旅游产业。(2)湖南省不同地级市的旅游产业效率存在明显的空间差异,部分地市的旅游产业增长速度低于经济增长速度,一些地市的旅游产业效率波动较大。(3)旅游产业效率演化受不同阶段生产单元利用水平及交通、资源、专业化、信息化、产业结构等因素的影响。

Hormesis has emerged as a more common and fundamental dose-response model than the threshold or linear-no-threshold(LNT) models

在回顾传统的有阈和线性无阈的剂量-反应关系的基础上,分析此类该模型被毒理学领域认同的主要原因和其在预测低剂量效应中的缺陷,进而提出了高剂量接触呈现抑制效应,而低剂量却呈现促进或刺激作用这一全面的激效兴奋性剂量-反应关系,弥补了现有模型的不足,并充分论证这种激效性剂量-反应关系在不同种属、接触因素和生物学终点中的普遍性,并探讨了不同物质的激效兴奋作用的可能机制以及激效兴奋模型的三大优点,最后提出了激效模型谋求广泛接受的现实困难和发展趋势。

The Criticism and Amendment for the Dual-Factor Model of Mental Health: From Chinese Psychological Suzhi Research Perspectives

Aiming at the limitations of psychopathology (PTH), the dual-factor model of mental health (DFM) was proposed as a new mental health concept and methodology under the background of positive psychology trend. In this paper we propose giving an overview of DFM, and doubt, criticize, and modify DFM from the perspective of Chinese psychological suzhi research. The available literature from 1983 to 2012 that is related to DFM and concerning psychological suzhi research in the past 20 years has been reviewed. In addition, we also absorbed the idea of positive psychology and Traditional Chinese Medicine (TCM) Constitution theory to develop theoretically the relationship model between psychological suzhi and mental health. The relationship model between psychological suzhi and mental health modifies and transcends PTH and DFM. It will be the new research area of mental health research.

Local and generalized height-diameter models with random parameters for mixed,uneven-aged forests in Northwestern Durango,Mexico

Background:We used mixed models with random components to develop height-diameter(h-d) functions for mixed,uneven-aged stands in northwestern Durango(Mexico),considering the breast height diameter(d) and stand variables as predictors.Methods:The data were obtained from 44 permanent plots used to monitor stand growth under forest management in the study area.Results:The generalized Bertalanffy-Richards model performed better than the other generalized models in predicting the total height of the species under study.For the genera Pinus and Quercus,the models were successfully calibrated by measuring the height of a subsample of three randomly selected trees close to the mean d,whereas for species of the genera Cupressus,Arbutus and Alnus,three trees were also selected,but they are specifically the maximum,minimum and mean d trees.Conclusions:The presented equations represent a new tool for the evaluation and management of natural forest in the region.

A prediction model for horizontal run-out distance of landslides triggered by Wenchuan earthquake

The peak ground acceleration （PGA）, the volume of a sliding mass V, the height of a mountain HL and the slope angle θ of a mountain are four important parameters affecting the horizontal run-out distance of a landslide L. Correlations among them are studied statistically based on field investigations from 67 landslides triggered by the ground shaking and other factors during the Wenchuan earthquake, and then a prediction model for horizontal run-out distance L is developed in this study. This model gives due consideration to the implications of the above four parameters on the horizontal run-out distance L and the validity of the model is verified by the Donghekou and Magong Woqian landslides. At the same time, the advantages of the model are shown by comparing it with two other common prediction methods. The major findings drawn from the analyses and comparisons are： （1） an exponential relationship exists between L and log V, L and log HL, L and log PGA separately, but a negative exponential relationship exists between L and log tan0, which agrees with the statistical results; and （2） according to the analysis results of the relative relationship between the height of a mountain （H） and the place where the landslides occur, the probabilities at distances of2H/3-H, H/3-2H/3, and O-H/3 are 70.8%, 15.4%, and 13.8%, respectively, revealing that most landslides occurred at a distance of H/2-H. This prediction model can provide an effective technical support for the prevention and mitigation of landslide hazards.