高坝泄洪雾化工程防护措施研究进展

高坝泄洪形成的雾化现象对枢纽下游建筑物运行、两侧岸坡稳定及生态环境可能造成危害,严重时可危及枢纽本身安全。伴随着系列原型观测、数学模型及物理模型试验等形成的雾雨强度预测技术的发展,泄洪雾化工程防护由被动的雾化—破坏—修复逐渐演变为在预测雨强及其范围基础上进行工程防护,并逐步与消能建筑物、高边坡的分区、分段防护相结合。通过对系列工程雾化防护措施调研,对高坝泄洪雾化工程防护相关研究成果进行归纳总结,认为不同防护材料在不同雨强的破坏特性及雾化对生态环境的影响是今后泄洪雾化工程防护措施研究的重要方向。     

流域水沙资源优化配置研究综述

水沙合理配置是影响河流健康的重要环境课题,正确认识水沙灾害和水沙利用的相互关系,开展流域水沙资源联合优化配置研究具有重要意义。本文系统地分析与总结了流域水沙资源联合优化配置研究的进展状况,包括局部流域的水土保持规划、水库水沙联合调度运用、灌区水沙输移分配和全流域范围的水沙资源优化配置理论与数学模型研究现状,探讨了目前流域水沙资源优化配置理论、模型、方案和评价中存在的问题,提出了未来流域水沙资源优化配置研究的发展方向。     

水资源脆弱性评价研究进展

水资源是影响区域、国家甚至全球环境可持续发展的关键,水资源脆弱性是制约水资源安全的基础性问题。本文从水资源脆弱性的概念、评价指标体系和评价方法方面,综述了国内外水资源脆弱性评价的研究进展,并对其未来的发展方向进行了展望。     

“生态水文学”学科发展和研究方法概述

生态水文学作为解决现代水问题的新方式,源于解决环境问题的新思考方式——“生态工程”,以“生态水文”为主题的论文、专著、会议成蓬勃发展之势.目前研究方法概述有:①国内外多种相关监测计划的建立以及各种估算方法相结合;②流域对比、传统的宏观和基于集对原理的微观相关分析揭示机理;③多种生态水文模型与遥感技术相结合模拟生态水文过程.未来发展方向主要归纳如下:①亟待生态水文学解释与水分驱动生态系统演化相关的重大问题;②寻找生态恢复的合适尺度,通过模型尽可能描述水量平衡及水文过程;③亟待开展极端事件对气候变化和人类活动的响应研究;④加强古生态学研究,在长时间序列中识别长期生态水文演变.     

黄土高原土壤侵蚀规律研究方向与途径

从黄土高原水土保持生态建设和黄河治理开发重大实践的需求出发,回顾了我国关于黄土高原土壤侵蚀规律研究的主要进展,分析了存在的问题,论述了深化黄土高原土壤侵蚀规律研究的重大需求,就黄土高原土壤侵蚀规律的研究方法与途径、研究方向与内容提出建议,认为应加强以下几方面的研究:重力侵蚀规律、不同治理措施配置下坡面-沟道系统侵蚀产沙耦合关系及泥沙输移规律、植被措施作用下的水文效应和产流机制、土壤侵蚀产沙发生发展过程尺度转换、黄土高原水土流失模拟理论与技术等;研究途径包括建设黄土高原土壤侵蚀试验观测体系、运用土壤侵蚀模型模拟与反演技术等。     

雪冰中黑碳的研究进展

黑碳气溶胶是大气气溶胶的一种重要成分,沉降在雪冰中可减小雪冰表面的反照率,影响雪冰的融化过程,导致全球和区域气候变化。黑碳气溶胶沉降在雪冰中产生的辐射强迫效应值得关注。中国是黑碳气溶胶排放大国,雪冰黑碳的问题值得关注。现简要介绍雪冰中黑碳研究的意义,着重综述雪冰中黑碳的来源,历史环境记录,现有的计算雪冰中黑碳对反照率影响的方法以及其辐射强迫效应的研究。对未来雪冰中黑碳的研究进行了展望,提出3点今后需加强研究的内容。     

E-Finance: An Introduction

E-finance is defined as “The provision of financial services and markets using electronic communication and computation”. In this paper we outline research issues related to e-finance that we believe set the stage for further work in this field. Three areas are focused on. These are the use of electronic payments systems, the operations of financial services firms and the operation of financial markets. A number of research issues are raised. For example, is the widespread use of paper-based checks efficient? Will the financial services industry be fundamentally changed by the advent of the Internet? Why have there been such large differences in changes to market microstructure across different financial markets?     

购买力平价理论的实证检验法综述

本文介绍了自 2 0世纪 70年代以来开放经济理论的基石———购买力平价及实际汇率的相关实证检验方法。以发达国家双边汇率作为样本数据进行检验 ,发现在样本期间足够长、样本数量足够多的情况下 ,PPP假设成立。此外 ,由于实际汇率对PPP的均值复归呈现出显著的非线性特征 ,今后的研究方向应当是建立非线性汇率动态模型。     

Ranking Journals Using Social Science Research Network Downloads

I use a new approach to rank journals, namely the number and percent frequency of articles a journal publishes that are heavily downloaded from the Social Science Research Network (SSRN). I rank 18 accounting and finance journals, and I identify five journals not considered by the two most recent major published ranking studies of publications by accounting faculty, namely (in rank order): Journal of Financial Economics, Review of Accounting Studies, Review of Quantitative Finance and Accounting, Journal of Corporate Finance, and Journal of International Financial Management and Accounting. I show that financial accounting faculties are more likely to post their working papers to SSRN, and papers posted by financial faculties generate more downloads. I mitigate this bias in favor of the financial area by providing separate rankings based on authors in the financial versus non-financial areas.     

Involving suppliers in product development: Insights from R&D directors and project managers

While there is increasing evidence that involving suppliers in new product development (NPD) is important, and for many firms even inevitable, there is also evidence that not all such efforts are successful. Firms aiming at implementing this strategy effectively have to pay close attention to several contingency factors on the organizational level and properly manage supplier involvement on the project level. The exploratory case study research underlying this article explores key issues to be considered when involving suppliers in NPD and the counter measures they can take. Our research shows that companies differentiate between so-called “know-how” and “capacity” projects, and that they manage them differently. Furthermore, this research shows that firms outside the automotive and high-tech manufacturing industries are likely to intensify supplier involvement in the future.