我国海洋生态文明建设重大问题探讨   总被引：1，自引：0，他引：1       下载免费PDF全文

许妍  梁斌  兰冬东  鲍晨光  于春艳  马明辉  关道明 《海洋开发与管理》2016,33(8):26-30

海洋在我国经济社会发展中占有极为重要的地位,是保障国家安全、缓解陆域资源紧张、拓展国民经济和社会发展空间的重要支撑系统。海洋生态文明建设作为国家生态文明建设的重要组成部分,是一项长期任务和系统工程。文章从海洋生态文明建设的内涵与意义出发,深刻分析当前海洋生态文明建设面临的形势与存在的问题,提出海洋生态文明建设的主要任务和重大项目工程,期冀为推进我国海洋生态文明建设作出贡献。  相似文献   

海洋生态文明建设对海域使用论证工作的具体指导          下载免费PDF全文

于大涛  杜红  王旭  高范  崔雷 《海洋开发与管理》2016,33(1):109-112

海洋生态文明建设是我国生态文明建设的重要组成部分。海域使用论证作为各类用海项目用海可行性分析的技术性分析工作,在论证工作中引导用海项目贯彻海洋生态文明建设理念,落实海洋生态文明建设具体方案,极具现实意义。文章按照海域使用论证工作流程,依据海洋生态文明建设具体方案,按阶段分析了海域使用论证工作的具体工作内容,以求通过海域使用论证工作落实海洋生态文明建设对用海项目的具体指导。  相似文献   

南海某导管架海洋平台倒塌分析     

唐友刚  朱龙欢  李焱  刘成义  张少洋 《海洋工程》2016,34(2):105-110

针对在役老龄导管架平台进行倒塌计算分析,确定极限承载力进而评估老龄导管架的安全裕度。采用非线性有限元方法,考虑平台的波流载荷及桩-土的非线性相互作用,利用SACS软件建立导管架整体三维有限元计算分析模型,并用逐步加载的方式,对南海某导管架平台进行了全过程非线性倒塌分析。计算分析表明,该导管架平台极限强度很高,具有较大的安全裕度;导管架倒塌过程呈逐步破坏形式,先是撑杆屈服,造成局部结构破坏,然后是钢桩发生屈服,降低结构承载力,最后节点逐步失效,造成结构倒塌。揭示了导管架平台结构失效倒塌的机理,给出了倒塌分析的可行方法和步骤。  相似文献   

Factors driving riverbed scouring and sedimentation in the Bayangaole to Toudaoguai reaches of the Upper Yellow River     

Suzhen Hou  Ping Wang  Yan Guo  Tian Hu 《地理学报(英文版)》2016,26(9):1305-1320

The Inner Mongolia reaches of the Yellow River face problems of severe sedimentation caused by a variety of complex factors. The sedimentation process in those reaches has been characterized using the sediment balance method, and the key factors affecting the process have been analyzed using the correlation analysis method. The results show that during the period 1952–2012 the Bayangaole (Bayan Gol) to Toudaoguai reaches in Inner Mongolia have undergone successive processes of accumulative sedimentation, then relative balance, and then accumulative sedimentation once again. The total annual sedimentation is 12.0341×10⁸ m³, of which accumulations from July to October account for 95.1% and the reaches from Sanhuhekou to Toudaoguai account for 98.5%. The main factor affecting scouring and sedimentation of the Bayangaole to Sanhuhekou reaches is the combined water and sediment condition. The critical conditions for equilibrium are an incoming sediment coefficient < 0.007 kg·s·m^–6 and a flow discharge > 700 m³·s^–1. The main factor affecting scouring and sedimentation of the Sanhuhekou to Toudaoguai reaches is the incoming sediment from the tributaries on the south bank and the combined water and sediment condition of the main stream. The critical conditions of the main stream for maintaining equilibrium status are a flow discharge of the main stream exceeding 800 m³·s^–1 and a comprehensive incoming sediment coefficient < 0.005 kg·s·m^–6. The incoming sediment from the tributaries has little impact on the main stream when the annual sediment load is less than 0.1×10⁸ t. The incoming sediment coefficient of the main stream and the incoming sediment from the tributaries both play vital roles in the riverbed evolution of the Inner Mongolia reaches, but the latter contributes the most.  相似文献   

崇明岛东滩湿地芦苇光合作用对土壤水盐因子的响应     

戚志伟  姜楠  高艳娜  李艳  王开运  张超 《湿地科学》2016,(4):538-545

2015年3~10月,在崇明岛东滩湿地设置7块采样地,以不同水盐条件下生长的芦苇(Phragmites australis)为材料,应用便携式光合系统分析仪(Li-6400),对芦苇的光响应特征进行实地测定,探讨芦苇光合过程对干旱和盐胁迫的响应机理。结果表明:1各月采样日的水位与土壤电导率显著负相关(n=420,p0.01),适当增加土壤水位,有利于降低土壤电导率,从而缓解植物盐胁迫伤害;28月21日的芦苇叶片净光合速率、蒸腾速率和气孔导度与水位显著正相关(n=42,p0.01),而与土壤电导率显著负相关(n=42,p0.01);胞间CO2浓度与水位和土壤电导率不相关。当水位高于-50 cm,净光合速率随着水位下降而降低,非气孔因素可能是净光合速率下降的主要原因;当水位低于-50 cm时,土壤电导率高于10 m S/cm,叶片蒸腾速率快速降低,水分利用效率不断提高,芦苇叶片以较低的净光合速率来适应干旱胁迫和盐胁迫;芦苇叶片通过降低最大净光合速率、暗呼吸速率、光补偿点和光饱和点等光合生理特征来适应干旱胁迫和盐胁迫;芦苇叶片净光合速率和最大净光合速率对土壤水盐因子具有高度相关性,可以作为土壤水盐胁迫程度的反应指标。因此,在芦苇快速生长阶段,合理调控水位,对芦苇光合作用具有重要意义。  相似文献   

Degrading river network due to urbanization in Yangtze River Delta   总被引：1，自引：0，他引：1  

Longfei Han  Youpeng Xu  Chaogui Lei  Liu Yang  Xiaojun Deng  Chunsheng Hu  Guanglai Xu 《地理学报(英文版)》2016,26(6):694-706

Evolution of river systems under the background of human activities has been a heated topic among geographers and hydrologists. Spatial and temporal variations of river systems during the 1960s–2010s in the Yangtze River Delta (YRD) were investigated based on streams derived from the topographic maps in the 1960s, 1980s and 2010s. A list of indices, drainage density (Dd), water surface ratio (WSR), ratio of area to length of main streams (R), evolution coefficient of tributaries (K) and box dimension (D), were classified into three types (quantitative, structural, and complex indices) and used to quantify the variations of stream structure. Results showed that: (1) quantitative indices (Dd, WSR) presented decreasing trend in the past 50 years, and Dd in Wuchengxiyu, Hangjiahu and Yindongnan have decreased most, about 20%. Structurally, the Qinhuai River basin was characterized by significant upward R, and K value in Hangjiahu went down dramatically by 46.8% during the 1960s–2010s. Decreasing tendency in D was found dominating across the YRD, and decreasing magnitude in Wuchengxiyu and Hangjiahu peaks for 7.8% and 6.5%, respectively in the YRD. (2) Urbanization affected the spatial pattern of river system, and areas with high level of urbanization exhibited least Dd (2.18 km/km²), WSR (6.52%), K (2.64) and D (1.42), compared to moderate and low levels of urbanization. (3) Urbanization also affected the evolution of stream system. In the past 50 years, areas with high level of urbanization showed compelling decreasing tendency in quantitative (27.2% and 19.3%) and complex indices (4.9%) and trend of enlarging of main rivers (4.5% and 7.9% in periods of the 1960s–1980s and the 1980s–2010s). In the recent 30 years, areas with low level of urbanization were detected with significant downward trend in Dd and K. (4) Expanding of urban land, construction of hydraulic engineering and irrigation and water conservancy activities were the main means which degraded the river system in the YRD.  相似文献   

Experimental study of motion characteristics of rock slopes with weak intercalation under seismic excitation   总被引：1，自引：0，他引：1  

Zhen-Lin Chen  Xiao Hu  Qiang Xu 《山地科学学报》2016,13(3):546-556

In order to investigate the effect of a weak intercalation on slope stability, a large-scale shaking table model test was conducted to study the dynamic response of rock slope models with weak intercalation. The dynamic response of the prototype slopes were studied in laboratory with the consideration of law of similitude. The initiation failure was observed in the rock slope model with a counter-tilt thin-weak intercalation firstly, not in the slope model with a horizontal thin-weak intercalation. Furthermore, it was interesting that the fracture site is shifted from crest top to the slope surface near the weak intercalation, which is different with the location of failure position in a normal layered slope. We also discussed the effect of the dip angle and the thickness of weak intercalation on the failure mechanism and instability mode of the layered rock slope. From the experimental result, it was noted that the stability of the slope with a counter-tilt weak intercalation could be worse than that of the other slopes under seismic excitation. The findings showed the difference of failure in slopes with a horizontal and counter weak intercalation, and implicated the further evaluation of failure of layered slopes caused by seismic loads.  相似文献   

Altitudinal trends in δ<Superscript>13</Superscript>C value,stomatal density and nitrogen content of <Emphasis Type="Italic">Pinus tabuliformis</Emphasis> needles on the southern slope of the middle Qinling Mountains,China     

Xian-zhao Liu  Chang-chun Gao  Qing Su  Yong Zhang  Yan Song 《山地科学学报》2016,13(6):1066-1077

In this study, a coniferous tree species (Pinus tabuliformis Carr.) was investigated at a moderate-altitude mountainous terrain on the southern slope of the middle Qinling Mountains (QLM) to detect the trends in carbon isotope ratio (δ¹³C), leaf nitrogen content (LNC) and stomatal density (SD) with altitude variation in north-subtropical humid mountain climate zone of China. The results showed that LNC and SD both significantly increased linearly along the altitudinal gradient ranging from 1000 to 2200 m, whereas leaf δ¹³C exhibited a significantly negative correlation with the altitude. Such a correlation pattern differs obviously from that obtained in offshore low-altitude humid environment or inland high-altitude semi-arid environment, suggesting that the pattern of increasing δ¹³C with the altitude cannot be generalized. The negative correlation between δ¹³C and altitude might be attributed mainly to the strengthening of carbon isotope fractionation in plants caused by increasing precipitation with altitude. Furthermore, there was a remarkable negative correlation between leaf δ¹³C and LNC. One possible reason was that increasing precipitation that operates to increase isotopic discrimination with altitude overtook the LNC in determining the sign of leaf δ¹³C. The significant negative correlation between leaf δ¹³C and SD over altitudes was also found in the present study, indicating that increases in SD with altitude would reduce, rather than enhance plant δ¹³C values.  相似文献   

Length of stay in urban areas of circular migrants from the mountainous areas in China     

Ming-hong Tan  Xiu-bin Li  Jian-zhong Yan  Liang-jie Xin  Lai-xiang Sun 《山地科学学报》2016,13(5):947-956

Currently, there is limited literature dealing with the length of stay of circular migrants in urban areas (LSCMU), although many studies have discussed the phenomenon of migration and the determinants of migration. This study attempts to fill that gap using survey data from the mountainous areas of Chongqing, Southwest China. From a comparative perspective, this study divided workers into two groups (a young group aged between 16 and 35 years and an old group aged between 36 and 65 years). The average LSCMU values for the young and old groups were 225 days and 174 days, respectively. Two multi-regression models were used to estimate the determinants of LSCMU in the two groups. The results showed that LSCMU was closely related to individual factors in both groups, including gender, age and job training. Family and community factors, including household size, arable land per capita and the distance from market, had much weaker effects on the dependent variable, especially in the older group. It was noticeable that job training had significant positive effects on LSCMU in both groups; these findings have special implications for the urbanization process in China.  相似文献   

Biodegradation of <Emphasis Type="Italic">Enteromorpha</Emphasis> polysaccharides by intestinal micro-community from <Emphasis Type="Italic">Siganus oramin</Emphasis>     

Zhibiao Zhang  Xuefeng Han  Yan Xu  Jin Li  Yuanyou Li  Zhong Hu 《中国海洋大学学报(英文版)》2016,15(6):1034-1038

Micro-communities are supposed to have more potential functions of biodegradation of polysaccharides than single strain; however, the intestinal micro-communities involved in the biodegradation of Enteromorpha polysaccharides (EP) were seldom reported. In order to obtain the EP-degrading micro-community, the intestines of Siganus oramin was obtained to isolate the micro-communities, which were enriched by 0.3% of EP as the sole carbon source. A stable micro-community with EP degradative capability was achieved after seven generations of subculture, named H1. Results showed that H1 was able to degrade 75% of EP within 24 hours, and the activity of EP lyases reached 500 U mL^?1 in 32 hours. With denaturing gradient gel electrophoresis (DGGE) and 16S rRNA gene clone library analysis, ten bacteria closely related to Marinomonas pontica, Microbacterium sp., Leucobacter chironomi, Cyclobacterium sp., Algoriphagus winogradskyi, Pseudoalteromonas sp. and Vibrio sp. were determined. Furthermore, compared with the DGGE bands sequence and the clone library analysis, the dominant bacteria of the EP-biodegrading micro- community were Pseudoalteromonas sp. and Vibrio sp., with the respective proportion of 38% and 46%, and they should play an important role in EP degradation together with other degrading bacteria in the micro-community H1.  相似文献