Can we predict the future food production? A sensitivity analysis

An attempt is made to assess the sensitivity of food production to various aspects of global change and environmental degradation during the next few decades. As a tool for this study a spreadsheet accounting system for food demand and supply is used. Taking into account the uncertainties of the various influencing factors, such as new technologies, improved management, increased fertilizer use, climatic change, expansion of irrigation, soil degradation and loss of agricultural land, the study indicates that one cannot say with any certainty whether or not food supply will meet expected demand in 2025, especially in Less Developed Countries. Bringing into use 10% of available potential cropland will make little difference.     

江南南部—华南北部前汛期严重旱涝诊断分析

利用江南南部—华南北部区域18个站45年（1951～1995年）4～6月降水资料计算了Z指数,确定出该区域严重涝年（1954、1962、1968、1973、1975年）和严重旱年（1958、1963、1967、1985、1991年）。分析了严重旱涝的频数分布和空间分布的特征,以及印度洋和太平洋整个赤道地区的SSTA、OLR距平场的分布。结果表明旱涝年SSTA、OLR距平场均有明显的差异。     

松辽盆地三肇地区油田储层裂缝及地应力特征

在大量裂缝发育特征的观察和统计工作基础上,结合油田开发动态和古构造发育史分析等,应用岩芯古地磁定向,差应变和波速各和异性等研究方法,结果认为三肇地区扶杨油层发育的裂缝走向以近东西向为主,多具高倾角,并可构成规模较大的主裂缝,其在油田注水开发中起着不可轻视的作用。分析表明,裂缝发育的密度与砂层的厚度成反比,与构造曲率成正比。区域最大水平主应力为北西西向,近东西向裂缝为油田最有效裂缝组系。     

广东省地方防震减灾工作思路与实践

防震减灾的四个环节,包括地震重点监视防御区的工作和实现全省防震减灾十年目标的任务,最终实施都得依赖市,县地地震工作机构的落实。根据广东省的政治,经济,社会发展以有震情特点,介绍了近两个来地方防震减灾工作的思路与实践,为今后的工作有益的借鉴。     

滨海附近地区GPS和断层形变与地震关系研究

简要介绍了环勃海及华北部分地区跨断层形变资料的分析结果,同时介绍了１９９２年至１９９５年首都圈两期ＧＰＳ测量资料处理分析的初步结果。通过比较,二者所显示的地壳活动趋势存在性质上的差异,主要是因观测时段的不一致而引起;在同时段资料的对比分析中,因测点和断层空间分布差异的存在,有４４．８％的流动资料难以判定其与ＧＰＳ资料的一致性,但在可判定的３３项资料中,有８９％是一致的,证明二者从不同的侧面反映了近     

粘土-MMH体系对赤潮生物的絮凝作用机制研究

根据粘土表面改性对其絮凝作用影响的理论模型,提出在粘土中引入ＭＭＨ（混合金属层状氢氧化物正电胶体）的改性方法,考察了ＭＭＨ浓度及ｐＨ值对絮凝作用的影响。结果表明,粘土中引和ＭＭＨ后,显著提高了对赤潮异弯藻（Ｈｅｔｅｒｏｓｉｇｍａａｋａｓｈｉｖｏ）和新月菱形藻（Ｎｉｔｚｃｈｉａｃｌｏｓｔｅｒｉｕｍ）的去除效率,二者的适宜配比为ＭＭＨ;粘土＝０．１ｇ：１ｇ,在此基础上,进一步研究了ＭＭＨ促进粘土絮凝作     

非精确搜索一维全局最优化方法

研究一维全局最优化问题的确定性求解方法。运用逐次建立目标函数的线性下界函数,将不含全局最优解的子区域删除,并基于非精确搜索结合下降算法而得出非精确搜索一维全局最优化方法,使计算量减少且使迭代收敛加快。迭代结束时该算法得到一维全局最优化问题的ε－全局最优解。该方法具有有限收敛性且不需精确的局部优化过程。文中的数值实例表明该算法的有效性。     

Controlling factors on the charging process of oil and gas in the eastern main sub-sag of the Baiyun Sag,Zhujiang River (Pearl River) Mouth Basin

The eastern main sub-sag (E-MSS) of the Baiyun Sag was the main zone for gas exploration in the deep-water area of the Zhujiang River (Pearl River) Mouth Basin at its early exploration stage, but the main goal of searching gas in this area was broken through by the successful exploration of the W3-2 and H34B volatile oil reservoirs, which provides a new insight for exploration of the Paleogene oil reservoirs in the E-MSS. Nevertheless, it is not clear on the distribution of “gas accumulated in the upper layer, oil accumulated in the lower layer” (Gas_upper-Oil_lower) under the high heat flow, different source-rock beds, multi-stages of oil and gas charge, and multi-fluid phases, and not yet a definite understanding of the genetic relationship and formation mechanism among volatile oil, light oil and condensate gas reservoirs, and the migration and sequential charge model of oil and gas. These puzzles directly lead to the lack of a clear direction for oil exploration and drilling zone in this area. In this work, the PVT fluid phase, the origin of crude oil and condensate, the secondary alteration of oil and gas reservoirs, the evolution sequence of oil and gas formation, the phase state of oil and gas migration, and the configuration of fault activity were analyzed, which established the migration and accumulation model of Gas_upper-Oil_lower co-controlled by source and heat, and fractionation controlled by facies in the E-MSS. Meanwhile, the fractionation evolution model among common black reservoirs, volatile reservoirs, condensate reservoirs and gas reservoirs is discussed, which proposed that the distribution pattern of Gas_upper-Oil_lower in the E-MSS is controlled by the generation attribute of oil and gas from source rocks, the difference of thermal evolution, and the fractionation controlled by phases after mixing the oil and gas. Overall, we suggest that residual oil reservoirs should be found in the lower strata of the discovered gas reservoirs in the oil-source fault and diapir-developed areas, while volatile oil reservoirs should be found in the deeper strata near the sag with no oil-source fault area.     

海藻生物制药推动海洋强国建设研究进展

海藻细胞内含有丰富的多糖,是未来海洋生物医药研究领域的前沿热点。目前,海藻多糖积累主要聚焦于大型海藻,与大型海藻相比,海洋微藻具有种类繁多、操作简单、测定精准等优势,是亟待挖掘的有潜力的海洋生物医药的种质资源。文章从药用海藻资源的开发、药用海藻资源的培养、海藻生物制药的环境保障分析入手,分析海洋生物制药存在的瓶颈,挖掘切实可行的解决途径,提出“海洋微藻生物制药全链条”新理念,为助推海洋强国建设、提升海洋生物医药的经济效益和市场竞争力奠定基础。     

台风海况下半潜式钻井平台动力性能监测与分析

半潜式钻井平台在海洋油气资源开发中发挥着重要作用,目前主要采用模型试验和数值模拟方法对其动力性能进行研究,非常缺乏台风等极端海况下半潜式平台动力响应的实海域监测数据。以某半潜式钻井平台为研究对象,构建了一套比较完善的平台动力性能监测系统,并对台风“杜苏芮”过境阶段的监测数据进行了分析。根据平台艏部气隙及运动监测数据推算了平台吃水及环境波高;采用随机波浪的统计分析方法,计算得到短期海况的有效波高、谱峰周期、能量谱等信息,通过与多种典型海浪谱对比发现Jonswap谱与所测波谱吻合较好;对平台的横摇、纵摇及垂荡运动进行了时域统计分析和频域谱分析,得到了台风海况下被测平台波频运动的实际响应特征,对于指导平台抗台作业具有重要意义。