Modeling the Influence of Dynamic Zoning of Forest Harvesting on Ecological Succession in a Northern Hardwoods Landscape

Dynamic zoning (systematic alteration in the spatial and temporal allocation of even-aged forest management practices) has been proposed as a means to change the spatial pattern of timber harvest across a landscape to maximize forest interior habitat while holding timber harvest levels constant. Simulation studies have established that dynamic zoning strategies produce larger tracts of interior, closed canopy forest, thus increasing the value of these landscapes for interior-dependent wildlife. We used the simulation model LANDIS to examine how the implementation of a dynamic zoning strategy would change trajectories of ecological succession in the Great Divide Ranger District of the Chequamegon–Nicolet National Forest in northern Wisconsin over 500 years. The components of dynamic zoning strategies (number of zones in a scenario and the length of the hiatus between successive entries into zones) and their interaction had highly significant impacts on patterns of forest succession. Dynamic zoning scenarios with more zones and shorter hiatus lengths increased the average amount of the forest dominated by early successional aspen (Populus sp.). Dynamic zoning scenarios with two zones produced more late successional mature northern hardwoods than scenarios with four zones. Dynamic zoning scenarios with very short (30 years) or very long (120 years) hiatus lengths resulted in more late successional mature northern hardwoods than scenarios with intermediate hiatus lengths (60 and 90 years). However, none of the dynamic scenarios produced as much late successional mature northern hardwoods as the static alternative. Furthermore, the amounts of all habitat types in all dynamic zoning scenarios fluctuated greatly in time and space relative to static alternatives, which could negatively impact wildlife species that require a stable amount of habitat above some minimum critical threshold. Indeed, implementing dynamic zoning scenarios of different designs would have both positive and negative effects on wildlife species and for other objectives of forest management.     

静电除尘器的新应用及其发展方向

静电除尘器广泛应用于冶炼、水泥和电站锅炉等工业领域。在简单介绍传统静电除尘器的分类及结构的同时，列举了目前使用的一些新型的静电除尘器，对静电除尘器在除去气体污染物、异味等方面的新应用进行了概述，并对于使用电凝并、无电晕式等除尘新机理也作了原理性的介绍。     

几种电缆隧道防火措施

通过对电缆隧道内加设防火墙、防火门，对电缆孔、洞进行防火封堵，安装火灾报警系统和气体灭火系统，提出对工程关键工艺及技术方面采取多项保护措施。     

中压加氢裂化装置危险和可操作性研究

针对中压加氢裂化生产过程存在很大的火灾、爆炸、毒害等危险性的特点，以加氢裂化反应器出口至冷高压分离器进口之间管线为分析节点，对工艺参数流量可能发生的各种偏差进行了危险和可操作性研究，找出了偏差发生的原因及可能导致的后果，提出了相应的控制措施，对提高装置的安全可靠性，预防和减少事故发生具有重要作用。     

汇源大厦托换工程沉降监测分析

汇源大厦托换工程影响巨大，其由立柱拆除引起的沉降监测属高精度要求的大型建筑物变形测量，是托换工程实施的重要保障，结合对托换梁、柱的结构受力分析，分3层布设监测点、依工程进展状况制定合理的观测周期，并采取重点监测与验证相结合的原则，使用精密水准仪配加游标卡尺的特制标卡尺的的特制标尺，多台仪器同时观测等方法，及时反馈了梁柱变形动态，指导拆除及托换进程，保证了工程的顺利进行。     

Characterization of fine organic particulate matter from Chinese cooking

PM2.5 samples were collected by a three-stage cascade impactor at two kinds of Chinese restaurants to characterize fine organic particulate matter from Chinese cooking sources. Major individual organic compounds have been quantified by GC/MS, including series of alkanes, n-alkanoic acids, n-alkanals, alkan-2-0nes and PAHs.Alkanes and ketones make up a significant fraction of particle-phase organic compounds, ranging from C11 to C26,and (C9 to C19, respectively. In addition, other organic compound classes have been identified, such as alkanols,esters, furans, lactones, amides, and nitriles. The mass concentrations of fine particles, alkanes, n-alkanoic acids and PAHs in air emitted from the Uigur style cooking are hundreds times higher than ambient PM2.5in Beijing.     

Preparation and emission characteristics of ethanol-diesel fuel blends

The preparation of ethanol-diesel fuel blends and their emission characteristics were investigated. Results showed the absolute ethanol can dissolve in diesel fuel at an arbitrary ratio and a small quantity of water(0.2% ) addition can lead to the phase separation of blends. An organic additive was synthesized and it can develop the ability of resistance to water and maintain the stability of ethanol-diesel-trace amounts of water system. The emission characteristics of 10%, 20%, and 30% ethanol-diesel fuel blends, with or without additives, were compared with those of diesel fuel in a direct injection(DI) diesel engine. The experimental results indicated that the blend of ethanol with diesel fuel significantly reduced the concentrations of smoke, hydrocarbon(HC), and carbon monoxide(CO) in exhaust gas. Using 20% ethanol-diesel fuel blend with the additive of 2% of the total volume, the optimum mixing ratio was achieved, at which the bench diesel engine testing showed a significant decrease in exhaust gas. Bosch smoke number was reduced by 55%, HC emission by 70%, and CO emission by 45%, at 13 kW/1540 r/min. However, ethanol-diesel fuel blends produced a few ppm acetaldehydes and more ethanol in exhaust gas.     

基于GIS的台风灾害损失评估模型研究

由于台风灾害所造成的损失有些是无法用精确的数学模型来描述,其损失可能是一个区间值。为准确及时地了解台风灾害过程中可能造成灾害损失等级的大小,选择了降水量、降水强度、最大风速、经济易损性作为评价的指标。采用可拓分析方法,将评价指标及其特征值作为物元,通过计算综合关联度判断灾害损失的等级;建立基于GIS的台风灾害损失评估模型,以实现台风灾害的动态评估。     

Characterization of modified Alternanthera philoxeroides by diethylenetriamine and its application in the adsorption of copper(II) ions in aqueous solution

Environmental Science and Pollution Research - By a simple and convenient method of using epichlorohydrin as linkages, a novel Alternanthera philoxeroides (AP) derivative modified with...     

VOCs催化燃烧的非贵金属催化剂研究进展

挥发性有机化合物（ VOCs） 是大气污染的主要来源之一,催化燃烧是有效的VOCs处理技术,而非贵金属催化剂是催化燃烧技术研究的热点。综述了多种结构形式的非贵金属催化剂的种类、活性组分及其催化性能的研究进展,探讨了水含量、杂质气体等因素对催化剂活性的影响。指出：将催化剂的制备和机理研究与实际应用中的工艺计算和设计相结合,开发用于VOCs催化燃烧的高活性、高稳定性、价格低廉的催化材料和工艺是今后的研究方向。