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221.
研究了iFIX组态软件在楼宇自动化系统中的应用.系统具有强大的监视、控制和管理功能,以及良好的互操作性和可扩展性.系统不仅能实时显示楼宇设备的各种数据,而且把数据的变化以动画的方式表现出来.  相似文献   
222.
采用先进的绝热加速量热仪为手段,对二甲亚砜的热稳定性进行了系统研究,其内容涉及纯二甲亚砜的热稳定性、加酸碱和硫化物等杂质后二甲亚砜的热稳定性,包括初始放热温度、温升速率、温度-压力等;通过修正试验数据,消除了热惰性因子的影响;得到了二甲亚砜的热稳定性特性。研究表明,在酸、碱存在时,二甲亚砜在室温下即可发生强烈的放热反应,导致二甲亚砜的分解温度提前。该实验研究结果,对二甲亚砜的安全生产工艺过程控制具有重要参考价值。  相似文献   
223.
根据丁二烯工业中事故多发的主要原因分析了丁二烯过氧化物的危险性,利用热爆炸理论计算了它的热爆炸临界温度,并提出了防止事故发生的主要方法,为丁二烯工业的安全生产提供指导。  相似文献   
224.
长庆油房庄油田水经过处理后仍具有较高的矿化度、较多的悬浮物及残留油,同时其SRB严重超标。现场处理水质不稳定,在进行回注时与地层的配伍性较差。针对这些情况,研究了一种新型的水处理工艺技术。对成垢离子调整剂、水质净化剂和成垢离子钝化剂进行了筛选,并对含油污水的成垢离子含量及比例进行了调整。运用这种技术,使油房庄油田水经处理后达到回注水的标准,且提高了与地层的配伍性。同时提出了新型水处理技术的工艺流程。  相似文献   
225.
在一体式一膜生物反应器处理生活污水的基础上,考察了运行过程中膜污染情况。试验结果表明,膜外表面沉积污泥是造成膜污染的主要因素,在活性污泥混合液中搓洗膜丝,是一种方便而有效的清洗方式。间歇式运行方式的停抽期间最低剩余抽吸压力可用来表征运行过程中膜过滤性能的变化。  相似文献   
226.
227.
We examined the principal effects of different information network topologies for local adaptive management of natural resources. We used computerized agents with adaptive decision algorithms with the following three fundamental constraints: (1) Complete understanding of the processes maintaining the natural resource can never be achieved, (2) agents can only learn by experimentation and information sharing, and (3) memory is limited. The agents were given the task to manage a system that had two states: one that provided high utility returns (desired) and one that provided low returns (undesired). In addition, the threshold between the states was close to the optimal return of the desired state. We found that networks of low to moderate link densities significantly increased the resilience of the utility returns. Networks of high link densities contributed to highly synchronized behavior among the agents, which caused occasional large-scale ecological crises between periods of stable and high utility returns. A constructed network involving a small set of experimenting agents was capable of combining high utility returns with high resilience, conforming to theories underlying the concept of adaptive comanagement. We conclude that (1) the ability to manage for resilience (i.e., to stay clear of the threshold leading to the undesired state as well as the ability to re-enter the desired state following a collapse) resides in the network structure and (2) in a coupled social–ecological system, the systemwide state transition occurs not because the ecological system flips into the undesired state, but because managers lose their capacity to reorganize back to the desired state. An erratum to this article can be found at .  相似文献   
228.
The recreational-use value of hiking in the Bellenden Ker National Park, Australia has been estimated using a zonal travel cost model. Multiple destination visitors have been accounted for by converting visitors’ own ordinal ranking of the various sites visited to numerical weights, using an expected-value approach. The value of hiking and camping in this national park was found to be $AUS 250,825 per year, or $AUS 144,45 per visitor per year, which is similar to findings from other studies valuing recreational benefits. The management of the park can use these estimates when considering the introduction of a system of user pays fees. In addition, they might be important when decisions need to be made about the allocation of resources for maintenance or upgrade of tracks and facilities.  相似文献   
229.
This study integrated aerial photographs from 1952, 1981, and 1998, and a satellite image from 2000 with oral histories and socioeconomic surveys to assess changes in forest and land cover in Ang Nhai village, Laos. The study documents the history of resource use and changes in household access to resources in the village. Three distinctive trends were observed in terms of forest and land cover—forest degradation, deforestation, and regeneration. Project results suggest that land and forest cover change dynamically under different circumstances. The case study also points out that integration into the market economy can induce intensification of unused lowland areas, while removing pressures from upland areas previously used for supplementing agricultural production. In addition, the creation of a national reserve forest to restrict local access and forest use was an ineffective tool for regulating encroachment and logging activities.  相似文献   
230.
Removal of selenate from water by zerovalent iron   总被引:1,自引:0,他引:1  
Zerovalent iron (ZVI) has been widely used in the removal of environmental contaminants from water. In this study, ZVI was used to remove selenate [Se(VI)] at a level of 1000 microg L(-1) in the presence of varying concentrations of Cl-, SO(2-)4, NO(-)3, HCO(-)3, and PO(3-)4. Results showed that Se(VI) was rapidly removed during the corrosion of ZVI to iron oxyhydroxides (Fe(OH)). During the 16 h of the experiments, 100 and 56% of the added Se(VI) was removed in 10 mM Cl- and SO(2-)4 solutions under a closed contained system, respectively. Under an open condition, 100 and 93% of the added Se(VI) were removed in the Cl- and SO(2-)4 solutions, respectively. Analysis of Se species in ZVI-Fe(OH) revealed that selenite [Se(IV)] and nonextractable Se increased during the first 2 to 4 h of reaction, with a decrease of Se(VI) in the Cl- experiment and no detection of Se(VI) in the SO(2-)4 experiment. Two mechanisms can be attributed to the rapid removal of Se(VI) from the solutions. One is the reduction of Se(VI) to Se(IV), followed by rapid adsorption of Se(IV) to Fe(OH). The other is the adsorption of Se(VI) directly to Fe(OH), followed by its reduction to Se(IV). The results also show that there was little effect on Se(VI) removal in the presence of Cl- (5, 50, and 100 mM), NO(-)3 (1, 5, and 10 mM), SO(2-)4 (5 mM), HCO(-)3 (1 and 5 mM), or PO(3-)4 (1 mM) and only a slight effect in the presence of SO(2-)4 (50 and 100 mM), HCO(-)3 (10 mM), and PO(3-)4 (5 mM) during a 2-d experiment, whereas 10 mM PO(3-)4 significantly inhibited Se(VI) removal. This work suggests that ZVI may be an effective agent to remove Se from Se-contaminated agricultural drainage water.  相似文献   
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