中国2005年社会核算矩阵的构建及其应用

文章在构建中国2005年宏观及居民账户细分的社会核算矩阵的基础上,利用SAM乘数模型,考察了各类产业的产出及居民收入效应以及外生冲击和转移支付的收入再分配效应。结果显示,产出和居民收入乘数较高的行业分别是那些与其他行业具有较高关联度的行业和劳动密集型行业;中国当前的经济增长结构在一定程度上有利于改善当前城镇收入差距过大的现状,但不利于缩小城镇居民和农村居民之间的收入差距;转移支付对改善当前城镇居民收入差距过大的现实有一定的促进作用,但改善力度不大,而转移支付对缩小城乡收入差距没有起到明显的积极作用。国家自然科学基金资助项目(70671086

Study of hydrodynamics and its impact on mariculture carrying capacity of Sanggou Bay:observation and modeling

主要介绍了从动力学研究桑沟湾养殖容量的主要思路、方法及结果。研究以精细过程观测为基础,以数值模型为手段,从物理海洋学角度考察养殖海区水动力特征,研究水动力对物质循环的影响、对颗粒态/溶解态营养物质的补充和对养殖生物量的影响,探寻不同养殖模式效果的技术路线;介绍了两个航次设计方案与目的。通过观测发现养殖对水动力垂直结构有很大影响,底层流速最大并滞后表层,发现弱动力条件下海底颗粒物和营养盐无法进入水体上层的事实。据此提出双边界层动力模型,建立一维数值模型进行机制探讨,将养殖阻力三维化建立水动力数值模型,定量给出养殖对水动力和水交换的阻碍;以此驱动三维养殖生态模型,充分考虑养殖对水动力的影响、水动力对生源要素的输运。建立了一个真正的物理-生物过程耦合模型。利用该模型进行的数值模拟和实验表明,贝藻兼养多元养殖是健康、高效养殖的有利措施;桑沟湾在现有养殖模式下,目前已基本达到了它的养殖容量,养殖品种分布不变,减少养殖密度至目前的0.9倍会略微提高产量,降低成本;减少湾口海带养殖密度,会大幅度提高贝藻兼养区的营养盐总量和养殖生物产量,从海带与贝类经济价值对比会有更高的效益。人为提高水动力混合或许是解决湾内营养盐缺乏的途径。The background and themes of dynamic study on mariculture carrying capacity of Sanggou Bay were described.The method used for this study was based on the fine processes observation,using physical oceanography theory and numerical model to examine the interaction between mariculture and hydrodynamics in Sanggou Bay.Design proposal and purposes for two cruises were introduced.Based on the observation we found that the kelp and the raft influenced the current vertical structure greatly,and the maximum velocity was at the lower layer with strong phase delay.It was also found that the damped current was too weak to mix the sediment detritus and nutrients into the upper layer.Based on these discoveries a double drag-boundary hydrodynamic model was proposed by adding the aquaculture drag at surface.The mechanism of kelp influence on the current profile was studied numerically by a one-dimension model.Considering the kelp drag in the water column besides the boundary drag,a three-dimension hydrodynamic model was adopted to quantify the influence of the aquaculture on hydrodynamics and water exchange of Sanggou Bay.A physical-biological coupled aquaculture ecosystem model was established using DIN,POM concentration and phytoplankton with kelp biomass as variable.The simulation and numerical experiments showed that polyculture was a useful method for healthy and high-efficiency aquaculture.Sanggou Bay has nearly reached its capacity under present aquaculture mode.By cutting down aquaculture density to 0.9 fold of the present density,the total production of kelp will slightly increase and the cost will be reduced.Cutting down the kelp density at the mouth of the bay could greatly enhance the amount of nutrients and biomass in the kelp-bivalve-culture area in the inner side.Artificial mixing might bring more nutrients from seabed in the bay.国家基础研究规划重点项目(2006CB400602);国家重点基金项目(40830854)共同资

Some characteristics of energy exchange at the underlying surface of desert and oasis in Hexi Corridor

在河西走廊黑河地区沙漠和绿洲下垫面生态条件下,用涡旋相关法研究了能量输送的不同模式和日变化进程;以及两种生态条件下能量输送间可能存在的相互关系。在沙漠生态条件下,大部分净辐射用于显热散失,另一部分用于向地下传输,较少部分则用于潜热输送,其方向在白天向下,在夜间向上;其Bowen比为13.16。在绿洲的麦田生态条件下,能量输送的基本模式为:大部分净辐射用于潜热散失,其输送方向与沙漠相反,另一部分用于显热散失,其输送方向一般在午后约3h即由上传转为下传。土壤热通量在最大时一般不超过40W/m2。冠层光合作用固定的能量则更小,其数量级维持在10W/m2以下,小麦不同生长阶段各能量分量占净辐射的比例有所变化。麦田的Bowen比从分蘖期的0.33降到拔节期末的0.095。当有干热大风自沙漠吹向绿洲时观测了典型的绿洲效应,其能量输送模式发生很大变化,显热显著下传,地热流量减弱,潜热散失强烈,起风后约2h潜热甚至高于净辐射。表明沙漠的能量组分参与了麦田的能量平衡过程。 【英文摘要】 With eddy correlation,we studied the pattern and dinurnal variation course of energy transfer for the underlying surface of desert and wheat field in oasis and their possible relationship between two ecological conditions at Heihe River region in Hexi Corridor during the HEIFE project.In the desert,the most net radiation( Rn )was consumed by sensible heat( H )transfer,another part of Rn conducted into desert surface,and a small part of Rn was dissipated by latent heat( LE ) transfer on a fine ...中国科学院资助项目;;国家自然科学基金;;日本文部省资助项

Some biometeorological features of wheat field in the ecological conditions of oasis at the Heihe Region

观测分析了 HEIFE地区绿洲中麦田的一些微气候特征 ,结果表明 SPAC中水势随高度呈显著梯度分布 ,在土壤 -植物以及植物 -大气界面 ,水势值存在两个大的跳跃 ;水势廓线存在明显的日变化 ;SPAC各部分水势变化的起伏顺序是大气 >植物 >土壤 ,说明水势变化受植物水分代谢进程直至气象因子的强烈影响和控制。冠层上方近地面风温湿的时空剖面显示出白天与夜晚相比 ,大气混合得较好 ;日出前则大气较为稳定 ;在典型晴天条件下 ,麦田上方的大气存在内边界。其结构受来自沙漠干热风的影响和控制。冠层内部也存在着温度、湿度、CO2 浓度、PAR、蒸腾作用、光合作用、气孔导度和叶温的垂直梯度 ,其廓线的日变化主要受太阳辐射的强烈控制 ,同时也受冠层内部不同层面叶片水分代谢强弱以及土壤状况的影响 ,其温湿廓线表现出与冠层上方不同的变化模式。 【英文摘要】 We observed and analysed some characteristics of biometeorology over and within canopy in spring wheat field in the ecological conditions of oasis during HEIFE program.Water potential in SPAC appeared a well vertical profile and the profile showed an obvious diurnal variation.There were water potential jumps in the SPAC junction boundaries.Sequence of variation intensity for water potential in each part of the SPAC was atmosphere,plant and soil.It is shown that the water potential was influenced and control...中国科学院资助;; 国家自然科学基金!( No.94 870 0 4 );; 日本文部省资助!( No.0 2 0 4 1 0 4 3

Imitating trunk flexible mechanism

本装置属于机器人连接机构,其结构是由多节并联机构1、2、3串联而成。而每节并联机构由三个分支杆、上下两平台连接及铰链组成。由多节这样的并联机构串联起来,就构成了具有超多自由度的柔性臂机构。由于本机构能实现转动与移动的复合运动,因此具有较高的柔性避障钻洞能力。且还具有高的刚度和精度。</p

Imitating trunk flexible mechanism

本装置属于机器人连接机构,其结构是由多节并联机构1、2、3串联而成。而每节并联机构由三个分支杆、上下两平台连接及铰链组成。由多节这样的并联机构串联起来,就构成了具有超多自由度的柔性臂机构。由于本机构能实现转动与移动的复合运动,因此具有较高的柔性避障钻洞能力。且还具有高的刚度和精度。</p

A Narrow Channel Experimental Study on Flammability Characteristics of Thermally Thin Fuels under Simulated Microgravity Conditions

利用高度分别为10 mm, 12 mm和14 mm的水平窄通道对微重力环境下热薄材料表面的火焰传播、材料的可燃极限进行了地面实验模拟研究. 在环境氧气浓度为18%和21%, 气流速度为0-50 cm/s条件下, 窄通道模拟实验结果与已有微重力实验结果的对比分析表明:气流速度小于15-20 cm/s时, 高度为12 mm和14 mm的窄通道能较好模拟微重力条件下材料表面的火焰传播, 气流速度大于15-20cm/s时, 高度为10 mm的通道能较好模拟;高度为12 mm和14 mm的窄通道能够模拟热薄材料的可燃极限曲线, 而高度为10 mm的通道模拟的可燃极限曲线则出现一定偏差. 分析认为, 窄通道能够有效地限制浮力对流, 进而提供模拟微重力条件下材料燃烧特性的实验环境, 通道内的剩余浮力对流和通道壁面热损失可能是造成材料燃烧特性定量差别的主要原因