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.

Structure-Property Relationships and Models of Controlled Drug Delivery of Biodegradable Poly (D, L-lactic acid) Microspheres

An oil-in-water (O/W) solvent evaporation method was used to prepare biodegradable microspheresbased on poly(D,L-lactic acid) (PLA). Nifedipine, a hydrophobic drug, was chosen as a model molecule in the studyof drug entrapment and release. Effect of preparation conditions on the size, morphology, drug loading, and releaseprofiles of micropheres was investigated. Based on in vitro release experimental findings, a diffusion/dissolutionmodel was presented for quantitative description of the resulting release behaviors and drug release kinetics fromPLA microspheres analyzed. The mathematical models were used to predict the effect of microstructure on theresulting drug release. It provided an approach to determine the suitable structure parameters for microspheres toachieve desired drug release behaviors.

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.

Grey relationship analysis and grey forecasting modeling on thermal stability of synthetic single diamond

Through analyzing 7 Ib-type samples of synthetic single diamonds by their DTA and TG in air, we ascertained the extrapolated onset temperature on the curves of DTA as the characteristic temperature of their thermal stabilities. Based on the grey system theory, we analyzed 4 factors influential in the thermal stability by the grey relationship analysis, a quantitative method, and derived the grey relationship sequence, that is, the rank of the influence extent of 4 factors on the thermal stability. Furthermore, we established the grey forecasting model, namely GM(1,5), for predicting the thermal stability of single diamonds with their intrinsic properties, which was then examined by a deviation-probability examination. The results illustrate that it is reasonable to take the Extrapolated Onset Temperature in DTA as the characteristic temperature for thermal stability (TS) of Ib-type synthetic single diamonds. The nitrogen content and grain shape regularity of diamonds are dominating factors. Likewise, grain size and compressive strength are minor factors. In addition, GM(1,5) can be used to predict the thermal stability of Ib-type synthetic single diamonds available. The precision rank of GM(1,5) is ‘GOOD’.

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.

基于深度学习的塑性变形理论建模研究进展

传统塑性理论模型由于引入了适当的假设和简化,面对复杂变形机制和复杂变形条件时具有局限性。基于深度学习的理论建模作为数据驱动的建模新范式,具有精度高、通用性强的特点,是塑性理论建模的重要方向。介绍了深度学习的建模方法,如传统神经网络模型、物理启发式神经网络模型和神经算子网络,分析了各个模型的特点。总结了近年来基于深度学习的塑性理论建模方法在本构关系、损伤断裂模型、微观组织模型和多尺度模型等方面应用的研究进展,并分析了提高模型精度、泛化能力和可解释性的方法。最后提出了基于深度学习的塑性理论建模方法面临的挑战和未来发展方向。

海域地震动强度包络模型研究

人工模拟地震动是目前开展海洋工程结构抗震分析的主要地震输入分析。强度包络函数是人工模拟地震动的重要参数,决定了地震动的强度非平稳性特性,并对地震动持时起控制作用。目前的地震动强度包络模型均是基于陆域地震动记录统计分析得出,无法准确反应海域地震动的强度特性。因此,基于日本K-Net强震动观测台网的实测地震数据库,分析海域地震动在时域中强度分布特性;提出适用于海域地震动的三段式强度包络模型,回归得到震级M、震中距R及关键参数上升段t_(1)、强震平稳段ts、下降段衰减率c(无量纲)的计算表达式;研究震级、震中距对海域地震动强度包络模型的影响规律,并探讨海域地震动与陆域地震动强度包络模型的异同。研究结果表明:海域地震动强度包络模型中关键参数上升段t_(1)、强震平稳段ts、下降段衰减率c的取值范围分别为[13~52 s],[12~79 s],[0.037~0.173];震级对关键参数(t_(1)、t_(s)、c)的影响要大于震中距;与陆域地震动相比,海域地震动的强度包络模型的下降段衰减率c相差显著,且各关键参数的分布范围更大。

生态型县域生态系统服务时空格局及其协同关系——以国家全域旅游示范区江西省武宁县为例

[目的]分析生态型县域生态系统服务的时空变化及协同关系,为促进国家生态文明建设,实现生态保护和社会经济协调发展提供理论参考。[方法]以江西省武宁县为例,结合野外实测数据,运用InVEST模型评估了该区2000—2020年水源涵养、土壤保持、碳储存和粮食供给4种典型生态系统服务,在此基础上探讨了生态系统服务间的协同关系及其时空变化特征。[结果]①2000—2020年,武宁县单位栅格年平均水源涵养量从173.14 mm提升至283.92 mm,单位栅格年平均粮食供给量从3.52 kJ提升至5.34 kJ,两者均呈现增长趋势;土壤保持功能呈先减少,后增长,再减少的波动趋势;20 a间土壤保持功能下降了15.71%,而碳储存功能呈现微弱增长的趋势。②武宁县南部和北部的林地是水源涵养、土壤保持和碳储存的高值区;水域、建设用地及未利用地分布区域是水源涵养、土壤保持和碳储存的低值区;4种生态系统服务中,林地和耕地是生态系统服务功能发展的关键用地。③武宁县水源涵养、土壤保持和碳储存3者之间是协同关系,与粮食供给是权衡关系;“高—高”和“低—低”集聚的协同关系主要分布在高海拔的林地及水域,“高—低”和“低—高”集聚的权衡关系主要分布在耕地。[结论]2000—2020年武宁县生态系统服务功能整体呈上升趋势,未来应重点关注生态调节服务功能向资源价值的转化。

老年人家庭代际关系模式及其影响因素研究——基于代际双向报告的K均值聚类分析

在传统的代际关系模式研究中,数据往往来自家庭中父母或子女一方的报告,然而仅凭借“一面之词”对代际关系进行测量真的准确吗?这一问题的背后透视出当前国内相关研究中双向报告视角的缺失。利用2020年中国家庭追踪调查(CFPS)数据,运用K均值聚类分析及多层Logistic回归方法,探究当前中国老年人家庭中代际关系的双向报告状况、代际关系模式及其影响因素。研究结果表明:首先,老年父母的代际关系报告平均得分要略低于成年子女的报告平均得分,但两者间并不存在显著差异,代际利益假说未获支持。其次,基于双向报告的聚类结果,可将老年人家庭代际关系具体划分为结构维度上的“亲子一致型”、“亲近子疏型”、“亲疏子近型”模式与水平维度上的“亲子和睦型”、“亲子有隙型”、“亲子疏离型”模式。最后,从代际关系模式的影响因素来看,代际结构、老年父母特征及成年子女特征均会在结构维度与水平维度上产生显著影响,而家庭特征仅在水平维度上产生显著影响。简言之,两代人的年龄差距越大、父母年龄越小、子女年龄越大,越可能形成评价一致的代际关系;两代人的年龄差距越大、两代人的性别一致、父母年龄越小、父母获得子女支持以及在城镇家庭中,越可能形成和睦的代际关系。

早龄期机制砂混凝土抗压强度与弹性模量时效关系及本构模型试验研究

为了研究早龄期机制砂混凝土在单轴受压状态下抗压强度与弹性模量的时效关系和本构模型,通过对8组不同龄期的C60机制砂混凝土试件进行立方体抗压强度试验、静力受压弹性模量试验和单轴受压应力-应变曲线试验,并参考多种已有研究模型,建立了早龄期机制砂混凝土在单轴受压状态下的抗压强度与弹性模量时效关系模型和分段式应力-应变本构模型。结果表明,采用的抗压强度与弹性模量时效关系模型和分段式应力-应变本构模型与试验数据吻合效果理想,能够较好地描述早龄期C60机制砂混凝土在单轴受压状态下的力学性能。

中国加入CPTPP的农产品贸易效应研究--基于WITS-SMART模型

粮食安全是国家安全的基石,面对国际市场不稳定性,加入CPTPP有望为中国夯实农产品贸易韧性提供新契机。在考察中国与CPTPP国家农产品贸易竞合关系的基础上,运用WITS-SMART模型建立局部均衡分析框架,研究中国加入CPTPP的农产品贸易效应,结果发现:第一,中国农产品竞争力整体不强,但与CPTPP国家依存关系较高,双边贸易潜力在关税完全削减时充分释放。第二,零关税情境下,贸易创造效应普遍大于转移效应,中国对CPTPP多数国家农产品贸易规模大幅扩张,进口增长主要源自种植业、畜牧业部门以及加拿大、澳大利亚、英国、日本等国家,出口增长主要集中于种植业部门以及日本、英国、马来西亚、墨西哥等国家。第三,加入CPTPP显著改善了双边经济福利,不过关税损失较为严重。因此,中国应破除部门利益障碍,加强与墨西哥、日本、英国等国经贸联系以充分挖掘CPTPP国家市场潜力,释放贸易自由化福利,持续提高农产品出口质量和国际竞争力以应对加入CPTPP带来的挑战。

鄂尔多斯盆地蟠龙地区长6储层四性关系研究

针对蟠龙地区长6储层四性关系的研究与认识不足,利用蟠龙地区的测井数据、录完井数据、岩心分析和化验资料等资料进行整理与分析,对研究区储层岩性、物性、电性与含油性特征及其相互间的关系进行了研究。研究结果表明,①蟠龙地区长6油层组以长石砂岩为主;②储层平均孔隙度为8%,平均渗透率为0.79×10-3μm 2,属于低孔特低渗至低孔超低渗储层;③录井中岩心以油迹含油级别为主;④结合岩心测试资料建立了储层参数测井解释模型,并最终确定有效储层物性下限为:渗透率0.15×10^(-3)μm^(2),孔隙度5.5%,电阻率20Ω·m,声波时差215μs/m。研究了储层四性基本特征及其关系,并得出了蟠龙地区储层物性和含油性的电性解释图版,为后续蟠龙地区油层解释以及探明储量参数的确定提供了依据。

浮动基多机悬吊系统动力耦合响应分析

为了研究浮动基多机悬吊系统在不规则波作用下的动力耦合关系,首先利用动量定理和动量矩定理建立了浮动基机器人动力学模型,其次利用达朗贝尔原理建立了悬吊系统的动力学模型,并提出了系统动力学的耦合关系分析步骤;最后结合实例,仿真分析了浮动基多机器人协调悬吊系统在不同波高、不同波长比和不同起吊速度下动力耦合响应过程。结果表明,该系统的理论研究进行了补充和完善,同时也为浮动基多机悬吊系统在实际的吊运过程中,判断安全的吊运环境提供技术支撑。

深圳市轨道交通车站与土地利用互动性研究

城市轨道交通与土地利用发展相互影响,两者协调发展有助于缓解城市交通拥堵,是城市可持续发展的关键问题之一.利用中国深圳市1999年与2015年的建筑普查、土地利用以及轨道交通车站刷卡数据,从开发强度、用地信息熵、车站类型及早晚高峰客流量等多个指标精细化分析轨道交通车站运能与周边土地利用之间的内在联系,并引入“节点-场所”模型构建指标体系评价轨道交通车站与土地利用间的发展协调程度,利用k-means聚类分析将二者协调状态划分为从属状态、平衡状态及失衡状态.结果表明,随着轨道交通车站开发建设,深圳市轨道交通车站周边土地集约利用水平提高;车站客流量与周边土地利用指标的相关性显著,全天客流量与容积率和商办建筑面积显著正相关,早高峰客流量与居住建筑面积和建筑密度显著正相关,而与容积率显著负相关,晚高峰客流量则与商办建筑面积和道路网密度显著正相关.深圳市轨道交通车站与站点周边土地利用协调发展水平偏低,站点类型以节点和场所价值低度均衡发展的从属状态为主,而协调状态则较少且集中分布在中心区圈层.未来应进一步对失衡节点地区采取针对性的开发策略,提升集聚效应与服务水平.

宫颈癌患者及配偶二元应对与亲密关系的主体-客体互倚模型研究

目的 本研究通过主体-客体互倚模型(APIM)分析宫颈癌患者及配偶的二元应对和夫妻亲密关系间的关系,为医护人员制订干预措施来改善宫颈癌夫妻的应对水平和亲密关系提供理论参考。方法 采取便利抽样方法抽取2021年10月至2022年6月郑州大学第一附属医院收治的197对宫颈癌夫妻作为样本,采用二元应对量表和婚姻调适测定量表进行问卷调查,并通过构建APIM模型分析宫颈癌患者及其配偶的二元应对水平与亲密关系间的关系。结果 宫颈癌患者和配偶的二元应对均能够预测自身亲密关系(β=0.49、0.45,P<0.001),即主体效应明显;客体效应结果显示配偶的二元应对水平能够预测宫颈癌患者的亲密关系(β=0.44,P=0.005)。结论 宫颈癌夫妻的二元应对水平和亲密关系之间存在部分二元交互作用。医护人员应将宫颈癌夫妻看作一个整体,开展二元应对干预策略的制定,从而达到提升亲密关系、维持婚姻稳定家庭和谐的目的。

积极发展资源在减少青少年抑郁水平中的累积效应、关系模式及特定资源的作用

以1301名七年级学生为被试进行间隔两年的追踪研究,考察积极发展资源对青少年当前和两年后抑郁水平的累积效应、关系模式及特定资源的作用。结果发现:(1)积极发展资源对青少年当前和两年后抑郁水平的降低分别具有即时和延时的累积效应,其中积极发展资源对青少年当前抑郁水平的即时累积效应呈二次函数非线性正加速模式,而对青少年两年后抑郁水平的延时累积效应呈线性匀速模式。对于青少年当前的抑郁水平来说,在积极发展资源累积至四类前,青少年当前的抑郁在高水平上升;积极发展资源累积至四类后,青少年抑郁水平呈显著下降趋势;(2)与抑郁水平高度相关且位于前四位的积极发展资源为:建立目标和决策能力、清晰积极的身份认同、抗逆能力和与他人的联结。该四类高相关的积极发展资源对青少年当前和两年后抑郁水平的降低分别具有即时和延时的累积效应,且四类高相关的积极发展资源对青少年当前和两年后抑郁的累积效应均呈二次函数的非线性模式。

岩浆通道成矿核心内涵“两深一浅一通道”及其找矿意义

岩浆通道成矿模型的建立深刻改变了岩浆铜镍硫化物矿床成因研究的范式,成为该领域的研究前沿,而且已经成功地应用于找矿勘查中。该模型揭示了硫化物熔离与聚集成矿在空间上的不一致性以及成矿与相关玄武岩铂族元素强烈亏损的成因联系,很好地解释了为什么很多含矿岩体围岩贫硫化物的现象。笔者将该模型的核心内涵概括为“两深一浅一通道”,“两深”指成矿物质来源于地幔、硫化物熔离发生在深部,“一浅”指硫化物的聚集成矿主要发生在较浅的岩浆房,“一通道”指较稳定的岩浆通道更有利于成大矿。结合对典型矿床和成矿带的分析,笔者提出侵位较浅的、规模相对较大的岩体,其成矿潜力好于深部的岩浆通道相。因此,认为地表矿化并不是唯一可靠的、甚至不能作为最重要的找矿标志,要提高找矿效率(特别是隐伏矿床),首先要全面分析成矿带岩浆通道系统在不同区域的埋藏、剥蚀和暴露状况,目标岩体地质产状及其与围岩时代差异等宏观地质要素,查明深部通道相与浅部岩体空间分布和形成深度的差异,在此基础上,判断浅部岩体的位置、合理部署重点勘查区域、选择有效的勘查技术、定位目标岩体,进行钻探验证。