碳纤维布加固高温作用后的连续梁试验研究和功能可靠度分析

比较分析了五根混凝土连续梁在碳纤维布加固后的极限荷载、变形、裂缝、延性系数等指标.在实际加固工程中无法对钢筋混凝土连续梁梁项进行加固,因此在试验中采用CFRP来加固梁的跨中,增强其正截面的抗弯承载力,并利用梁支座处出现塑性铰,引起弯矩重分布的特性,来达到加固的目的.为使试验更加接近加固工程实际情况,试验中加固是在持载情况下进行的.试验研究表明：使用碳纤维布提高高温作用后的混凝土连续梁的方法,能有效地抵抗二次火灾的影响;基于试验结果,推导出高温作用后碳纤维布加固的实用设计方法,与试验数据可以较好地吻合.在不能找出加固后梁所有失效模式的情况下,利用分阶段平截面弹塑性分析法求出加固后连续梁的极限挠度,求出了梁的功能（挠度）可靠度.     

采伐影响下森林景观服务功能变化研究

文章以大兴安岭呼中林业局亚里河林场为研究区,以遥感数据、林相图和采伐设计资料为信息源,选择水源涵养、固土保肥、固定CO2和释放O2四项服务功能,运用景观生态学原理,引用相应模型,估算了研究区1989年和2000年服务功能价值及其空间分布变化;建立历年采伐分布图,计算采伐造成的服务功能价值损失,揭示该损失值与木材生产的经济效益之间的关系,并分析了服务功能价值在各管理区域内的分布。结果表明,1989年服务功能价值为1.85×108元,2000年为1.37×108元,价值20×104元h/m₂以上的面积明显下降。生态服务功能的下降由采伐导致,1989至1999年采伐导致的生态损失价值为0.71×108元,是木材生产获利的1.9倍,采伐损失价值与年出材量呈现相同的变化趋势。最后证明了管理等级区划和限制采伐量,即“天保工程”,将有利于森林植被恢复,大幅度提高整个亚里河林场的生态服务功能。     

河堤环境效应略论

河流堤防的初始环境效应主要是防止河水泛滥和与河川争地。其派生的主要环境效应有:抬高水位,增大流速;延迟或堵塞支流汇水;造成水资源的浪费和短缺;中断土地肥力的自然培育过程;破坏土壤表层盐分的自然洗涤机制;加速土地沙化进程;改变流域结构,破坏河流环境生态功能。为防止河水泛滥并侵占河流的生存空间而修筑堤防,却引起了环境质量下降甚至导致环境恶化,人类应从中汲取沉痛的教训。      

Alterations in Carbohydrate Metabolism in Selected Tissues of Crab,Oziotelphusa Senex Senex (Fabricius) Under Fenvalerate-Induced Stress

Changes in carbohydrate metabolism in hepatopancreas and muscle of the crab, Oziotelphusa senex senex exposed to a sublethal concentration (0.2 ppm) of fenvalerate, a pyrethroid insecticide, were studied. the glycogen and total carbohydrate levels decreased significantly in the tissues of crab exposed to fenvalerate. an increase in phosphorylase ‘a’ and decrease in aldolase activity levels suggested increased glycogenolysis, and decreased glycolysis during fenvalerate toxicity. Krebs cycle enzymes such as NAD-isocitrate dehydrogenase, succinate dehydrogenase and malate dehydrogenase were decreased, suggesting reduced mitochondrial oxidative metabolism. Glucose-6-phosphate dehydrogenase activity was increased significantly, indicating enhanced oxidation of glucose through the hexose monophosphate shunt pathway. Lactate dehydrogenase activity was elevated indicating the development of anaerobic conditions at tissue level in the stressed crab. Cytochrome C oxidase and Mg2+ ATPase activity levels were also decreased, indicating the impaired energy synthesis and prevalence of energy crisis. These results suggest that fenvalerate has a profound effect on the glucose metabolism of crab.     

Population Viability Analysis with Species Occurrence Data from Museum Collections

Abstract: The most comprehensive data on many species come from scientific collections. Thus, we developed a method of population viability analysis (PVA) in which this type of occurrence data can be used. In contrast to classical PVA, our approach accounts for the inherent observation error in occurrence data and allows the estimation of the population parameters needed for viability analysis. We tested the sensitivity of the approach to spatial resolution of the data, length of the time series, sampling effort, and detection probability with simulated data and conducted PVAs for common, rare, and threatened species. We compared the results of these PVAs with results of standard method PVAs in which observation error is ignored. Our method provided realistic estimates of population growth terms and quasi‐extinction risk in cases in which the standard method without observation error could not. For low values of any of the sampling variables we tested, precision decreased, and in some cases biased estimates resulted. The results of our PVAs with the example species were consistent with information in the literature on these species. Our approach may facilitate PVA for a wide range of species of conservation concern for which demographic data are lacking but occurrence data are readily available.     

Functional decomposition—A contribution to overcome the parameter space explosion during validation of highly automated driving

Abstract

Objective: Particular testing by functional decomposition of the automated driving function can potentially contribute to reducing the effort of validating highly automated driving functions. In this study, the required size of test suites for scenario-based testing and the potential to reduce it by functional decomposition are quantified for the first time.

Methods: The required size of test suites for scenario-based approval of a so-called Autobahn-Chauffeur (SAE Level 3) is analyzed for an exemplary set of scenarios. Based on studies of data from failure analyses in other domains, the possible range for the required test coverage is narrowed down and suitable discretization steps, as well as ranges for the influence parameters, are assumed. Based on those assumptions, the size of the test suites for testing the complete system is quantified. The effects that lead to a reduction in the parameter space for particular testing of the decomposed driving function are analyzed and the potential to reduce the validation effort is estimated by comparing the resulting test suite sizes for both methods.

Results: The combination of all effects leads to a reduction in the test suites’ size by a factor between 20 and 130, depending on the required test coverage. This means that the size of the required test suite can be reduced by 95–99% by particular testing compared to scenario-based testing of the complete system.

Conclusions: The reduction potential is a valuable contribution to overcome the parameter space explosion during the validation of highly automated driving. However, this study is based on assumptions and only a small set of exemplary scenarios. Thus, the findings have to be validated in further studies.     

The elaboration process – an approach for sustainable product development: a case study

Environmentally conscious product development, eco-design or design for environment is the methodology trying to introduce environmental requirements into product design. The first step of this process is the gathering of customer requirements for a structured product development procedure, such as quality function deployment (QFD). The problem is that environmental requirements are usually unspoken by the customers. This paper describes a methodology for uncovering such requirements by using environmental default questions in an elaboration process. This leads to an increased customer environmental awareness, and it generates a comprehensive list of requirements suitable for use in a subsequent QFD process. The effects of the elaboration process are demonstrated in one case study.     

Risk evaluation of natural disasters based on connection function

There are many uncertain factors,such as stochastic,fuzzy and gray information in the risk analysis on natural hazard.The set pair analysis(SPA)deals effectively with the various uncertain factors contributing to evaluation of the risk level of natural disasters.The evaluation indicators and standards of natural disasters risk are analyzed by identity-discrepancycontrary(IDC).The result,the connection numbers,still has uncertainty information.Thus,yielding the risk evaluation model of natural disasters based on connection function,which construct a set pair relation between the indicators of connection numbers and comprehensive evaluation standards,and describe uncertainty of the connection numbers by using connection function.The study showed that the proposed model takes into account only the uncertainty of risk evaluation indicator identification on natural disasters,also the uncertainty of result connection numbers.This approach gives full consideration to the uncertainty of systematic evaluation process along with the actual meaning of comprehensive evaluation functions.Therefore,this means it is able to reduce the uncertainty of final evaluation results and improve the accuracy and reasonability of evaluation results.This model is capable of reflecting actual situation of the risk evaluation on natural disaster affected by various uncertain factors and has a promotional value in the natural disaster risk assessment.     

Urban Land-banking Planning: A New Instrument to Regulate Urban Land Supply-demand of Nanjing City

Abstract

It is the major purpose of the paper to present the urban land-banking planning and its functions of promoting the urban land-banking system and land use administration. The urban land-banking system has the potential attribute of acting as an irreplaceable role in urban land administration, but its unexpected function-deviation has impacted its implementation effect in China. A few city governments are attempting to deal with the problem by the urban land-banking planning which is expected to contribute to the extension of urban function, optimization of urban patterns, promotion of urban core competitiveness and overall construction of the urban value chain. In this paper, we primarily discuss the necessity, functions, purposes and main contents of the urban land-banking planning. Subsequently, the implementing situation of the urban land-banking system in Nanjing is analyzed, including its integrated mode, spatio-temporal quantitative distribution and main characteristics. Finally, the background and targets including total, compositions, space, and regulation points are gradually introduced to present the Nanjing land-banking planning version 2.     

国土空间用途管制的改革逻辑及其规划响应路径

在完善生态文明制度体系、推进国家治理体系和治理能力现代化的宏观背景下,系统梳理土地用途管制制度起源、实施特点、成效与不足,重点解析土地用途管制向国土空间用途管制转型的改革逻辑及其对国土空间规划的具体要求,为完善国土空间规划体系提供借鉴。研究结果表明：（1）土地用途管制制度突出强调对耕地的保护,以新增建设用地为主要管控对象,建立了土地用途分类—规划—计划—审批—监管的完整管控链条,在保护耕地、保障粮食安全、倒逼节约集约用地和提高依法依规用地意识等方面取得了较好成效,但仍存在覆盖范围不全、管制刚性过强、生态用地管制乏力等不足。（2）国土空间用途管制以生态文明建设为逻辑起点,通过单一地类保护向空间统筹转型、地类管制向空间管控转型、指标传导为主向指标与分区相结合转型、底线约束向约束与引导并重转型,构建面向全过程、多样化的管制规则体系,完善空间传导机制,进而实现所有国土空间全要素统一管制。（3）面对国土空间用途管制的时代需求,国土空间规划改革应在系统性、整体性的规划管控指标体系、覆盖全域、上下衔接的规划分区体系、底线约束与激励引导相结合的规划实施弹性机制以及“全链条”管理机制等方面做出积极响应,进而实现不同层级国土空间规划和用途管制的统筹协调管控。