收缩城市建设用地利用效率时空分异及影响机制——以黑龙江省伊春市为例

建设用地是城镇经济社会活动的空间载体,其利用效率是调控建设用地扩张和配置的重要基础.论文以收缩型城市——黑龙江省伊春市为例,利用DEA模型测算了1995-2015年伊春市建设用地利用效率分析其时空演变规律,并运用地理探测器模型探究伊春市建设用地利用效率空间分异的影响机制,结论如下:①1995-2015年伊春市建设用地利...     

Assessing the potential of reservoir outflow management to reduce sedimentation using continuous turbidity monitoring and reservoir modelling

In‐stream sensors are increasingly deployed as part of ambient water quality‐monitoring networks. Temporally dense data from these networks can be used to better understand the transport of constituents through streams, lakes or reservoirs. Data from existing, continuously recording in‐stream flow and water quality monitoring stations were coupled with the two‐dimensional hydrodynamic CE‐QUAL‐W2 model to assess the potential of altered reservoir outflow management to reduce sediment trapping in John Redmond Reservoir, located in east‐central Kansas. Monitoring stations upstream and downstream from the reservoir were used to estimate 5.6 million metric tons of sediment transported to John Redmond Reservoir from 2007 through 2010, 88% of which was trapped within the reservoir. The two‐dimensional model was used to estimate the residence time of 55 equal‐volume releases from the reservoir; sediment trapping for these releases varied from 48% to 97%. Smaller trapping efficiencies were observed when the reservoir was maintained near the normal operating capacity (relative to higher flood pool levels) and when average residence times were relatively short. An idealized, alternative outflow management scenario was constructed, which minimized reservoir elevations and the length of time water was in the reservoir, while continuing to meet downstream flood control end points identified in the reservoir water control manual. The alternative scenario is projected to reduce sediment trapping in the reservoir by approximately 3%, preventing approximately 45 000 metric tons of sediment from being deposited within the reservoir annually. This article presents an approach to quantify the potential of reservoir management using existing in‐stream data; actual management decisions need to consider the effects on other reservoir benefits, such as downstream flood control and aquatic life. Copyright © 2012 John Wiley & Sons, Ltd.     

船舶气象导航随船验证

通过横流太平洋往返两个航次随船调查，研究了采用气象导航对减少燃油消耗和保证船舶安全、班期等，不但有定的经济效益，而且是一种非常有效的航运管理方法。     

新疆前兆震群ρ值的研究

研究新疆伊宁——乌鲁木齐和乌什——库尔勒1972年以来发生的49个震群的ρ值表明,ρ<0.55可作为前兆震群的判据指标。分析了ρ<0.55标准下的前兆震群的预测能力,认为,震群序列的ρ值具有一定的预报效能。     

The development of computer networks: First results from a microeconomic model

 Computer networks like the Internet are gaining importance in social and economic life. The accelerating pace of the adoption of network technologies for business purposes is a rather recent phenomenon. Many applications are still in the early, sometimes even experimental, phase. Nevertheless, it seems to be certain that networks will change the socioeconomic structures we know today. This is the background for our special interest in the development of networks, in the role of spatial factors influencing the formation of networks, and consequences of networks on spatial structures, and in the role of externalities. This paper discusses a simple economic model – based on a microeconomic calculus – that incorporates the main factors that generate the growth of computer networks. The paper provides analytic results about the generation of computer networks. The paper discusses (1) under what conditions economic factors will initiate the process of network formation, (2) the relationship between individual and social evaluation, and (3) the efficiency of a network that is generated based on economic mechanisms. Received: 5 July 2000 / Accepted: 28 November 2000     

Ozone Production Efficiency in Savanna and Forested Areas during the EXPRESSO Experiment

NO, NO_x, NO_y and O₃ have been measuredduring the airborne EXPRESSO experiment, November 96,which took place near Bangui (Central Africa) at thebeginning of the dry season. This period correspondsto an intense burning activity. Chemical andphotochemical characteristics of the planetaryboundary layer, which corresponds most of the time tothe monsoon layer, and the Harmattan layer, which issituated above the latter, have been studied forsavanna as well as rain forest areas. These two layersare very different when considering the chemicalcomposition (especially for ozone and NO_z) andthe photochemical age.The relationship of photochemical ozone productionversus photochemical NO_x oxidation products hasbeen investigated. Results indicate an ozoneproduction efficiency (OPE) ranging from 6.3 to 14.8in the planetary boundary layer. Thus, this layer ischaracteristic of a photochemically young and activeair mass. In this layer, the ozone potentialproduction increases with the air mass photochemicalage. On the other hand, the Harmattan layer shows anOPE ranging from 4.6 to 7.4. These values arecharacteristic of photochemically well-aged airmasses. In this layer, the ozone potential productionseems to be exhausted with values around 4.0 (i.e., 4ozone molecules produced for each NO_x moleculeemitted).     

一个有限差分大气环流模式的并行效率

适合于大规模并行处理机（ＭＰＰ）的中国科学院大气物理研究所新一代九层大气环流模式（ＩＡＰ ９Ｌ ＡＧＣＭ）被发展成功。本文描述了并行模式的设计原则，给出了该模式的并行版本在我国几种主要的并行机上的并行执行效率数据。采用消息传递方式（ＭＰＩ）的区域分解方法用于实现程序的并行，结果表明，对于该模式，只有一维区域分解方法才能取得较好的并行可扩展性，即随着处理器的增加而能得到相应较好的并行加速比和并行效率。     

测震学多项指标综合预测概率分析

通过对测震学各单项指标的预测效能调研，为进一步提取前兆信息，选择了7项测震学指标：频次、地震蠕变、6值、缺震、η值、GL值和调制比，进行综合概率分析。7项指标对关注地区的全时空扫描并考虑了空间单元异常与中强震地点对应的模糊关系，得到指标在各空间单元异常后发生中强震的条件概率。根据历史上每个单项指标的预报效能求计算综合概率时的指标权重，按贝叶斯定律得到相应不同指标在不同时间窗和不同空间单元时中强震发生的加权综合概率。计算结果（1970年以来）表明，对华北地区和川滇地区这一综合概率方法预测效能的R值评估超过0.5。     

山西沁水煤层气田采收率预测

采用地质类比、等温吸附曲线及储层数值模拟 3种方法对山西沁水煤层气田主力气层———二叠系山西组 3# 煤层、石炭系太原组 15 # 煤层的煤层气采收率进行了预测 ,结果 3# 煤层的煤层气采收率为 6 2 % ,15 # 煤层的采收率为 5 5 % ,总平均采收率为 5 9%。分析对比了这 3种方法的运用条件及优缺点 ,指出煤层气采收率的预测必须采用多种方法 ,并结合具体的煤层气地质特点进行综合分析 ,才能得出合理的结论。     

Effectiveness of structural control based on control energy perspectives

A computational algorithm for maximizing the control efficiency in actively controlling the elastic structural responses during earthquake is proposed. Study of optimal linear control using a single degree of freedom shows that applying active control is very effective in reducing the structural displacement and velocity responses for long‐period structures, but at the same time it has an adverse effect in increasing the absolute acceleration response. The extent of this adverse effect reduces the effectiveness of the control system, and therefore it poses a limit on the maximum control force in order to provide maximum control efficiency. In view of this shortcoming, maximum control energy dissipation is used to define the most effective optimal linear control law. Less displacement and velocity response are expected as larger control force is applied, but there is always a limit that maximum control energy can be dissipated. This study shows that this limit depends on the structural characteristics as well as the input ground motion, and a general trend is that the maximum control energy decreases as damping increases. Finally, application of the proposed algorithm on a six‐storey hospital building is presented to show the effectiveness of using optimal linear control on a multi‐degree‐of‐freedom system from the control energy perspectives. Copyright © 2001 John Wiley & Sons, Ltd.