真鲷能量收支和氮与碳收支的初步研究   总被引：3，自引：1，他引：3  

李军  徐长安  徐世宏  马道远  肖志忠 《海洋科学》1998,22(2):46-48

以真鲷 (起始体重 :1 1 .5～ 1 4.8g)为实验对象 ,在平均水温 2 4.5 7℃下 ,进行饱食状态下的真鲷幼鱼摄食 -生长实验 ,饵料为玉筋鱼 ;对其摄食量、生长及粪便进行直接测定 ,对能量收支、氮和碳收支各组份进行估计和计算。结果表明 ,真鲷幼鱼的能量分配对策是 ,需较多的能量维持其代谢需求 ,同时 ,有较多的氮和碳随代谢产物排出体外 ,从而导致较低的能量生长及物质生长。  相似文献   

Evaluating simplified models in predicting global seismic responses of a shake table–test building isolated by triple friction pendulum bearings     

Nhan D. Dao  Keri L. Ryan  Hieu Nguyen-Van 《地震工程与结构动力学》2019,48(6):594-610

This paper evaluates the ability of simplified superstructure models, including two shear frame models and a single-story model, in predicting global responses of a full-scale five-story steel moment-frame buildings isolated by triple friction pendulum bearings subjected to earthquake motions. The investigated responses include displacement of the isolation system, roof drift, story drift, and floor acceleration. Mechanical properties of the simplified superstructure models were derived from the modal information of a verified full 3-D model. The comparison between the analytical responses and experimental responses shows that the simplified models can well predict the displacement of the isolation system. Furthermore, the shear-frame models are adequate for predicting floor acceleration when the specimen is subjected to horizontal ground motions. However, when the specimen is subjected to 3-D motions, the shear-frame models un-conservatively predict floor acceleration. The full 3-D model improves the prediction of story drift compared with the simplified models for both horizontal and 3-D motions.  相似文献   

Pan evaporation modelling and changing attribution analysis on the Tibetan Plateau (1970–2012)          下载免费PDF全文

Hong Xie  Xuan Zhu  Dao‐Yang Yuan 《水文研究》2015,29(9):2164-2177

Pan evaporation (E_p) is an important indicator of water and energy and the decline of E_p has been reported in many regions over the last decades. The climate and E_p are dependent on each other. In this study, the temporal trends of E_p and main E_p drivers, namely mean air temperature (T_a), wind speed (u), global solar radiation (R_s), net long‐wave radiation(R_nl) and vapour pressure deficit (D) from 1970 to 2012, were calculated on the basis of 26 meteorological stations on the Tibetan Plateau. The arithmetic average of E_p from 26 stations decreased with the rate of ?11.91 mm a^?2; the trends of R_s, R_nl, T_a, u and D were ?1.434 w m^?2 decade^?1, 0.2511 w m^?2 decade^?1, 0.3590°C decade^?1, ?0.2376 m s^?1 decade^?1 and 9.523 Pa decade^?1, respectively. The diffuse irradiance is an essential parameter to model E_p and quantify the contribution of climatic factors to changing E_p. 60 724 observations of R_s and diffuse solar irradiance (R_d) from seven of the 26 stations were used to develop the correlation between the diffuse fraction (R_d/R_s), and the clearness index (R_s/R_o). On the basis of the estimation of the diffuse component of R_s and climatic data, we modified the PenPan model to estimate Chinese micro‐pan evaporation (E_p) and assess the attribution of E_p dynamics using partial derivatives. The results showed that there was a good agreement between the observed and calculated daily E_p values. The observed decrease in E_p was mostly due to declining wind speed (?13.7 mm a^?2) with some contributions from decreasing solar irradiance (?3.1 mm a^?2); and the increase of temperature had a large positive effect (4.55 mm a^?2) in total whilst the increase of R_nl had insignificant effect (0.35 mm a^?2) on E_p rates. The change of E_p is the net result of all the climatic variables. Copyright © 2014 John Wiley & Sons, Ltd.  相似文献   

Bonfires as a potential source of metal pollutants in urban soils,Galway, Ireland     

Ligang Dao  Liam Morrison  Chaosheng Zhang 《Applied Geochemistry》2012

Soils are recipients of contaminants from the burning of metal-containing materials in bonfires. In order to obtain a better understanding of the impacts of bonfires on soils, a total of 218 surface soil samples were collected from a traditional bonfire site in Galway City, Ireland. Concentrations of 14 elements including Al, Ca, Co, Cu, Fe, K, Mg, Mn, Na, Ni, Pb, Sc, Ti and Zn in 30 selected samples were determined using ICP-OES. Strong variations were observed for these elements. Concentrations of Zn, Cu and Pb were elevated, indicating that these metals may be influenced by human activities. Therefore, concentrations of these three metals were further measured using a portable X-ray fluorescence (P-XRF) analyser (n = 218) and their spatial distribution was investigated using a Geographical Information System (GIS). Soils with elevated metal concentrations, as evident from the spatial distribution maps, coincided with the locations of traditional festival bonfires. The results of this study provide useful information for the management of bonfire sites including the enforcement of a control policy regarding the burning of materials in bonfires.  相似文献   

Impact of climate and land-use changes on hydrological processes and sediment yield—a case study of the Be River catchment,Vietnam     

Dao Nguyen Khoi  Tadashi Suetsugi 《水文科学杂志》2013,58(5):1095-1108

Abstract

The impact of climate and land-use changes on hydrological processes and sediment yield is investigated in the Be River catchment, Vietnam, using the Soil and Water Assessment Tool (SWAT) hydrological model. The sensitivity analysis, model calibration and validation indicated that the SWAT model could reasonably simulate the hydrology and sediment yield in the catchment. From this, the responses of the hydrology and sediment to climate change and land-use changes were considered. The results indicate that deforestation had increased the annual flow (by 1.2%) and sediment load (by 11.3%), and that climate change had also significantly increased the annual streamflow (by 26.3%) and sediment load (by 31.7%). Under the impact of coupled climate and land-use changes, the annual streamflow and sediment load increased by 28.0% and 46.4%, respectively. In general, during the 1978–2000 period, climate change influenced the hydrological processes in the Be River catchment more strongly than the land-use change.