Modeling water and carbon fluxes above summer maize field in North China Plain with back-propagation neural networks

INTRODUCTION Dynamics of carbon and water vapor fluxesexchange between the atmosphere and the ecosystembiosphere, depend on complex and non-liner interplayamong physiological, ecological, biochemical andedaphic factors and meteorological conditions (Jarvis,1995; Leuning et al., 1995). There are many studiesquantifying the fluxes across different time and spacescales as well as assessing the environment con-straints on them by some kinds of biophysical orempirical models whose resul…     

城市群发展与地方政府间关系模式

城市群是中国区域经济发展和城市发展的重要战略举措。现阶段城市群发展所面临的问题凸显中国地方政府间关系的不适应性。城市群发展需要重构地方政府间关系,其基础是确立地方政府间相互依赖与合作的伙伴关系,重点是形成一种新的地方府际管理模式,关键是创建地方政府间新的治理机制。     

大体积混凝土污水处理工程的施工技术

为防止大体积砼产生裂缝，采用HE微膨胀剂与LNF泵送剂行之有效。同时应进行温度应力与浇筑长度验算和精心施工。     

Starting and Sustaining an Undergraduate Research Program: The SURIEM Experience at Michigan State University

Abstract

Mentoring undergraduate students in research is both rewarding and challenging. In this paper we present how we established a summer Research Experience for Undergraduates (REU) program in the mathematical sciences at Michigan State University. A goal of our REU is to include students who are at an early stage of their study of mathematics. We share our experiences in recruiting students, designing research projects, and mentoring our participants. We discuss the challenges we faced and the solutions we found while working with a diverse group of undergraduate students from across the nation.     

论城市文化形象的塑造

城市文化形象是城市文化的外在表征，更注重城市文化的外显性。城市文化形象具有地域性、交融性、集聚性和辐射性。良好的城市文化形象是城市无形的资产，是城市经济发展的推动力；凝聚着城市的灵魂，引导着市民的思维。研究城市文化形象特征，把握城市文化脉络的走向，设计和创造出充满地方特色、性格魅力和生命活力的现代城市形象。是城市文化形象塑造的重要任务。     

温度概念的热力学

热量是由温度来定义的,因而用热冷程度来定义温度就是不科学的.本文以热力学第一定律和第二定律为基础,用可逆热机的运转来建立温度概念.温度是体系的单一决定可逆热机效率的宏观可测性质.此一宏观可测性质的特征由可逆热机运转的三种情形可以明确地揭示出来.     

精准扶贫背景下广西义务教育均衡发展研究

精准扶贫是全面建设小康社会的重要举措,发展教育阻断贫困代际传递是我国精准扶贫的重要部分,教育推动社会进步和民族振兴,社会公平的实现以教育公平的实现为基石,实现教育公平重点在于推进义务教育的均衡发展。本文通过梳理以往研究成果,构建测度民族地区义务教育均衡发展的指标体系,以广西为例,实证民族地区的义务教育均衡发展现状,剖析广西义务教育发展的薄弱环节,顺应精准扶贫的大趋势,有针对性的补齐"短板",防止出现义务教育的"低度均衡"。     

Hybrid ants-like search algorithms for P2P media streaming distribution in ad hoc networks

Media streaming delivery in wireless ad hoc networks is challenging due to the stringent resource restrictions,po-tential high loss rate and the decentralized architecture. To support long and high-quality streams,one viable approach is that a media stream is partitioned into segments,and then the segments are replicated in a network and served in a peer-to-peer(P2P) fashion. However,the searching strategy for segments is one key problem with the approach. This paper proposes a hybrid ants-like search algorithm(HASA) for P2P media streaming distribution in ad hoc networks. It takes the advantages of random walks and ants-like algorithms for searching in unstructured P2P networks,such as low transmitting latency,less jitter times,and low unnecessary traffic. We quantify the performance of our scheme in terms of response time,jitter times,and network messages for media streaming distribution. Simulation results showed that it can effectively improve the search efficiency for P2P media streaming distribution in ad hoc networks.     

近代工业与唐山医疗事业的发展

城市医疗事业的发展是城市化进程中的必然产物。随着唐山近代工业的发展以及城市近代化,城市医疗事业也随之发展起来。城市各界积极推动唐山医疗事业的进步,而推力最大者,当属近代工业企业。     

基于GIS的现代信息技术在城市规划与管理中的应用前景

中国日益提高的城市化水平，对近年来以MIS为主的城市规划与管理的办公自动化模式提出了更高、更新的要求、论述了基于GIS的现代信息技术在城市规划与管理领域的应用前景及其对该领域的管理理念、技术手段将产生的深远影响．