气候变化对典型气象年数据的影响及能耗评估——以中国北方大城市天津为例     

熊明明  李明财  李骥  曹经福 《气候变化研究进展》2017,13(5):494-501

本文以中国北方城市天津为例,采用Sandia及Danish两种方法生成典型气象年（TMY）数据,并借助TRNSYS软件模拟得到3个时段（1961-1990年、1971-2000年和1981-2010年）典型办公建筑的逐时负荷,评估气候变化对典型气象年数据及模拟负荷的影响。结果表明：Sandia和Danish生成典型气象年的方法在天津均有较好的适用性,Sandia方法采用6个气象要素生成的典型气象年数据代表性满足要求。受气候变化影响,典型气象年数据变化较大,采暖期（11月-翌年3月）较制冷期（6-9月）的变化更明显;从30年均值差异看,1981-2010年相对于1961-1990年,建筑供热负荷减少5.2%,而制冷负荷增加1.6%。因此,在使用典型气象年数据进行建筑设计能耗评估时需充分考虑气候变化的影响,加快典型气象年数据的生成和更新工作。基于天津现行使用的典型气象年数据模拟得到的办公建筑制冷负荷较1981-2010年偏低6.7%,供热负荷偏高4.7%。表明采用现行典型气象年数据进行建筑能耗评估时,会造成制冷负荷偏低,供热负荷偏高,从而降低人体舒适度及造成供热能源浪费。  相似文献   

网络负载平衡技术及其在WebGIS中的应用     

杨睿  尹晖  郑慧 《地理空间信息》2010,8(1):53-55

分析传统的WebGIS结构和基于多服务器的WebGIS服务在应对海量和高峰数据时的不足,介绍网络负载平衡技术的思想,方法以及调度负载的决策方法,提出将网络负载平衡技术融入WebGIS结构设计中的理念和思想。采用DNS轮换的负载平衡策略给出测试数据证明该技术的应用效果并且给出基于网络负载平衡技术的WebGIS系统设计。  相似文献   

Sediment burial stimulates the growth and propagule production of Spartina alterniflora Loisel.     

Zifa Deng  Shuqing An  Congjiao Zhao  Lin Chen  Changfang Zhou  Yingbiao Zhi  Hongli Li 《Estuarine, Coastal and Shelf Science》2008,76(4):818-826

Spartina alterniflora Loisel., an extensively invasive species on the Chinese coast, is a focus of increasing management concern due to its high expansion rate in estuaries and tidal zone, and the significant damage it causes to native ecosystems. In order to understand the processes and mechanisms of invasion of S. alterniflora in China, the impact of three sediment types (sand, sand–loam mixture and loam) and five buried patterns (unburied, 50% burial of initial plant height, 75% burial of initial plant height, complete burial and repeated burial) on the growth of seedlings or ramets was investigated. Results showed that each of the three factors (sediment types, burial pattern and plant materials) and interactions between/among them, significantly affected height and clonal growth, and biomass accumulation and allocation. Plant height, total biomass and number of new vegetative propagules significantly increased with progressive burial treatments. However, the complete burial treatment resulted in the death of all plant materials, and the maximum values of three parameters were found in the 50% burial or repeated burial treatments. Plant responses were determined by the instantaneous thickness of sediment of each time burial rather than by the total quantity of repeated burial. The growth of S. alterniflora was not shown to be dependent on specific types of sediment in sedimentation environment. In contrast to the unburied control, the proportion of primary tillers produced directly from initial individuals and the ratio between the aboveground and belowground biomass were greater under burial treatments. Seedlings produced more new vegetative propagules than vegetative offspring in all experimental treatments, and the former were apt to produce ramets from rhizomes rather than primary tillers. It is concluded that under various sedimentation environments, the clonal spread efficiency of seedlings was higher than that of vegetative offspring, and there is a positive feedback relationship between sedimentation and the growth of S. alterniflora. Thus, moderate sedimentation may stimulate the invasion of exotic species, S. alterniflora in coastal China.  相似文献   

Efficient Approximate Method of Global Reliability Analysis for Offshore Platforms in the Ice Zone   总被引：1，自引：0，他引：1  

李刚  张大勇  岳前进  Eric  C.Spurgeon 《中国海洋工程》2008,22(2):303-311

Ice load is the dominative load in the design of offshore platforms in the ice zone, and the extreme ice load is the key factor that affects the safety of platforms. The present paper studies the statistical properties of the global resistance and the extreme responses of the jacket platforms in Bahai Bay, considering the randomness of ice load, dead load, steel elastic modulus, yield strength and structural member dimensions. Then, based on the above results, an efficient approximate method of the global reliability analysis for the offshore platforms is proposed, which converts the implicit nonlinear performance function in the conventional reliability analysis to linear explicit one. Finally, numerical examples of JZ20-2 MSW, JZ20-2NW and JZ20-2 MUQ offshore jacket platforms in the Bahai Bay demonstrate the satisfying efficiency, accuracy and applicability of the proposed method.  相似文献   

丹江口水库水体主要营养盐含量变化特征   总被引：4，自引：1，他引：3  

王文林  周瑞云  成庆利 《海洋湖沼通报》2008,(2):123-129

根据2000~2001年汉江丹江口水库水质监测资料,对水质整体状况和营养盐变化特征进行研究,结果表明,丹江口水库水质总体状况良好,库周气温和水温变化不大,pH值中性偏碱,白河站、丹江口站、凉水河站和清泉沟站的水质能够达到或优于地表水Ⅱ类水质要求;襄樊站污染较严重,其中主要为唐白河口和小清河口,两断面溶解氧较低,电导率、SS、CODMn、NH3-N、NO3-N、NO2-N、T-P等均出现峰值,说明工业、企业和城镇生活污水的点源和非点源排放较严重。  相似文献   

Top hat stiffeners: A study on keel failures     

Raju  B.G. Prusty 《Ocean Engineering》2010,37(13):1180-1192

The need to assess the structural capability of curved marine composite structures that support the keel of high performance yachts has increased due to the rise in the number of accidents and human casualties. The top hat stiffener is the basic structural member of the yacht to sustain the tensile and bending load of the keel. This paper characterises the mechanical strength of E-glass/vinylester composite top hat stiffeners subjected to transverse loading. The out-of-plane load transfer was studied and failure modes were identified for the three different composite layups which were tested to failure. Experimental results obtained from mechanical testing were compared with FEA predictions, based on the quadratic interlaminar stress criterion. Secondary reserve strength from the unidirectional fibres was identified and the potential to use this secondary strength was further investigated.  相似文献   

Theoretical and experimental study of Chen chaotic system with notch filter feedback control     

张晓明  陈菊芳  彭建华 《海洋学报(英文版)》2010,29(9)

Since the past two decades, the time delay feedback control method has attracted more and more attention in chaos control studies because of its simplicity and efficiency compared with other chaos control schemes. Recently, it has been proposed to suppress low-dimensional chaos with the notch filter feedback control method, which can be implemented in a laser system. In this work, we have analytically determined the controllable conditions for notch filter feedback controlling of Chen chaotic system in terms of the Hopf bifurcation theory. The conditions for notch filter feedback controlled Chen chaoitc system having a stable limit cycle solution are given. Meanwhile, we also analysed the Hopf bifurcation direction, which is very important for parameter settings in notch filter feedback control applications. Finally, we apply the notch filter feedback control methods to the electronic circuit experiments and numerical simulations based on the theoretical analysis. The controlling results of notch filter feedback control method well prove the feasibility and reliability of the theoretical analysis.  相似文献   

Nonlinear feedback synchronisation control between fractional-order and integer-order chaotic systems     

贾立新  戴浩  惠萌 《海洋学报(英文版)》2010,29(11)

This paper focuses on the synchronisation between fractional-order and integer-order chaotic systems. Based on Lyapunov stability theory and numerical differentiation, a nonlinear feedback controller is obtained to achieve the synchronisation between fractional-order and integer-order chaotic systems. Numerical simulation results are presented to illustrate the effectiveness of this method.  相似文献   

黄河三角洲潮滩孔压对循环振动荷载响应研究     

宋敬泰  贾永刚  孟祥梅  单红仙  郑杰文 《海岸工程》2010,29(2):1-9

为了研究黄河三角洲潮滩孔压对循环振动荷载的响应过程,在现场潮滩上利用循环振动荷载作用于海床,实时监测了振动过程中孔压的发展过程。研究结果表明:在每一轮振动过程中,超孔压并非是一直升高的,其发展过程主要可以分成3个阶段:首先是累积阶段,在此期间内超孔压迅速积累并达到一峰值,即"超孔压最大响应值";其次是过渡阶段,在此期间超孔压基本保持稳定;而后是消散阶段,即超孔压从最大响应值开始缓慢消散。在振动过程中,产生的最大超孔压是振动能量的指数函数,而且不同深度所产生的最大超孔压不同,存在一极值响应深度。在超孔压累积阶段,尽管不同深度超孔压的累积历程不同,但其累积形式具有一致性,即超孔压是以振动次数为自变量的二次函数,而且,超孔压的累积速率是线性降低的。  相似文献   

垂向动载荷下桶形基础响应实验研究     

矫滨田  鲁晓兵  张建红  时忠民 《海洋工程》2009,27(3):45-53

对垂向动载荷作用下吸力式桶形基础(简称桶基)响应进行离心机实验模拟.结果表明,在垂向动载荷作用下,当载荷幅值超过一定值时,桶基周围砂土软化甚至液化,发生明显的沉降.桶基周围土体的沉降随着载荷幅值的增加而增加.由于液化区的滤波和对动载的衰减作用,发生沉降的范围有限,离桶壁约一倍桶高距离.超孔隙水压从桶基边沿水平向逐渐衰减,从土面开始往下逐渐衰减到零.桶基周围砂土完全液化的厚度随载荷幅值的增加而增加,最大值约为桶高的40%.  相似文献