聚磷酸钙可降解纤维研究

为解决材料在环境中的降解问题,制备了聚磷酸钙纤维．研究表明其结构为无定形玻璃态,抗拉强度为１．９０ＧＰａ,弹性模量为６７．５ＧＰａ,并可发生化学降解,故可作为可降解复合材料的增强纤维     

落叶阔叶林释放异戊二烯的研究

生物释放的烯烃是全球气候变化和温室效应研究的重要内容之一。本研究在国内首次测定了华北落叶阔叶林内１０种乔、灌木的异戊二烯释放率,分别在０－１．２８μｇ．ｇ＾－１．Ｈ＾－１之间。探讨了林内异戊二烯的时空分布规律。发现高释放树种辽东栋的异戊二烯释放率呈昼夜周期性变化,在１４：００达到１．９２μｇ．ｇ＾－１．Ｈ＾－１,夜晚几乎降为０。对各环境因子进行排序：光照与异戊烯率的关系最为密切（ｒ＝０．８６５０）     

Influences of Climatic Change on Some Ecological Processes of an Insect Outbreak System in Canada's Boreal Forests and the Implications for Biodiversity

Insect outbreaks are a major disturbance factor in Canadian forests. If global warming occurs, the disturbance patterns caused by insects may change substantially, especially for those insects whose distributions depend largely on climate. In addition, the likelihood of wildfire often increases after insect attack, so the unpredictability of future insect disturbance patterns adds to the general uncertainty of fire regimes. The rates of processes fundamental to energy, nutrient, and biogeochemical cycling are also affected by insect disturbance, and through these effects, potential changes in disturbance patterns indirectly influence biodiversity. A process-level perspective is advanced to describe how the major insect outbreak system in Canadian forests, that of the spruce budworm (Choristoneura fumiferana Clem. [Lepidoptera: Tortricidae]), might react to global warming. The resulting scenarios highlight the possible importance of natural selection, extreme weather, phenological relationships, complex feedbacks, historical conditions, and threshold behavior. That global warming already seems to be affecting the lifecycles of some insects points to the timeliness of this discussion. Some implications of this process-level perspective for managing the effects of global warming on biodiversity are discussed. The value of process-level understanding and high-resolution, long-term monitoring in attacking such problems is emphasized. It is argued that a species-level, preservationist approach may have unwanted side-effects, be cost-ineffective, and ecologically unsustainable.     

Drivers of future streamflow changes in watersheds across the Northeastern United States

Accurate projections of streamflow, which have implications for flooding, water resources, hydropower, and ecosystems, are critical to climate change adaptation and require an understanding of streamflow sensitivity to climate drivers. The northeastern United States has experienced a dramatic increase in extreme precipitation over the past 25 years; however, the effects of these changes, as well as changes in other drivers of streamflow, remain unclear. Here, we use a random forest model forced with a regional climate model to examine historical and future streamflow dynamics of four watersheds across the Northeast. We find that streamflow in the cold season (November–May) is primarily driven by 3-day rainfall and antecedent wetness (Antecedent Precipitation Index) in three rainfall-dominant watersheds, and 30-day rainfall, antecedent wetness, and 30-day snowmelt in the fourth, more snowmelt-dominated watershed. In the warm season (June–October), streamflow is driven by antecedent wetness and rainfall in all watersheds. By the end of the century (2070–2099), cold season streamflow depends on the importance placed on snow in the machine learning model, with changes ranging from −7% (with snow) to +40% (without snow) in a single watershed. Simulated future warm season streamflow increases in two watersheds (56% and 193%) due to increased precipitation and antecedent soil wetness, but decreases in the other two watersheds (−6% and −27%) due to reduced precipitation.     

瓦斯抽采二次膨胀封孔材料膨胀机理及应用研究

为降低瓦斯抽采漏气,开发了1种具备后期膨胀的二次膨胀材料（DE）,以水泥基材料为对比样,利用自制的膨胀力测试装置,以XRD和SEM分别表征其膨胀力及微观结构。研究结果表明:相比水泥基材料,DE材料的膨胀力明显,并表现出显著的时间效应,且DE材料的膨胀力随约束刚度增大而增大;水化1 d时, DE材料较水泥基材料生成更多的钙矾石（AFt）晶体;随着DE材料水化,AFt晶体不断增多,且水化7 d后AFt晶体发生延迟膨胀,这是引起DE材料后期膨胀的主要因素;工程应用表明DE材料可提高瓦斯抽采浓度及纯量,有效改善抽采效果。     

Mineral constituents in Leccinum scabrum from lowland locations in the central Europe and their relation to concentration in forest topsoil

Leccinum scabrum is an edible mushroom common in European regions in the northern hemisphere. Macro and trace mineral constituents such as Ag, Al, Ba, Ca, Cd, Co, Cu, Fe, K, Mg, Mn, Na, Ni, Pb, P, Rb, Sr and Zn were studied in L. scabrum and in the top soil collected from the same location underneath soil substratum. The “pseudo-total” and labile (extractable fraction of minerals) were measured to get insight into the levels, distribution between the morphological parts of fruiting bodies, potential for their bioconcentration by mushroom and evaluated for human exposure via consumption of the mushroom. The sampling sites include the Dar?lubska Wilderness, Trójmiejski Landscape Park, Sobieszewo Island, Wdzydze Landscape Park and outskirts of the K?trzyn town in Mazury from the norther part of Poland. Median values of K, Rb and P concentrations in dehydrated L. scabrum were for caps in range 27,000–44,000 mg kg^?1, 90–320 mg kg^?1 and 6,200–9,100 mg kg^?1, and followed by Mg at 880–1,000 mg kg^?1, Ca at 48–210 mg kg^?1 and Al at 15–120 mg kg^?1. The median concentrations of Cu, Fe, Mn and Zn in caps were in range 15–27 mg kg^?1 db 38–140 mg kg^?1, 5.3–27 mg kg^?1 and 130–270 mg kg^?1. For Ba and Sr, concentrations on the average were at ～1 mg kg^?1, and almost equally distributed between the caps and stipes of the fruiting bodies. L. scabrum mushrooms were low in toxic Ag, Cd, Hg and Pb, for which the median values in dried caps from five locations were, respectively, in range 0.48–0.98 mg kg^?1 (cap to stipe index, Q_C/S, was 2.5–4.1), 1.0–5.8 mg kg^?1 (Q_C/S 2.9–3.8), 0.36–0.59 mg kg^?1 (Q_C/S 1.6–2.7) and 0.20–0.91 mg kg^?1 (Q_C/S 1.2–1.9). Substantial variations in the concentrations of the “pseudo-total” fraction (extracted by aqua regia) or labile fraction (extracted by 20% solution of nitric acid) of the elements determined in forest topsoils were noted between some of the locations examined. The elements K, P, Cd, Cu, Hg, Mn, Na, Rb and Zn can be considered as those which were bioconcentrated by L. scabrum in fruiting bodies, while the rates of accumulation varied with the sampling location.     

Achieving sustainable development goals through participatory forest management: Examples from South-Eastern Bangladesh

Forests managed through peoples' participation can help to achieve a number of sustainable development goals (SDGs). This paper, drawing data from four participatory forest management (PFM) projects in south-eastern Bangladesh, explored: (a) the factors that influenced the outcomes of PFM; and (b) contribution of PFM towards achieving selected SDGs. The research used observation, semi-structured household interviews, group discussions, vegetation survey and Ostromʼs design principles for data collection, Divergent forest conditions and factors in four PFM sites have had differential contribution to SDGs. Heterogeneity of user groups, insufficient coordination, absence of motivation, and land tenure conflicts had affected the attainment of SDGs. The PFM helped to achieve 9–11 SDGs comprising poverty reduction (Goal 1), improving food security (Goal 2), maintaining health and well-being (Goal 3), enhancing childrensʼ education (Goal 4), fair access to jobs and committees (Goals 5 and 10), sources of clean drinking water (Goal 6), affordable energy for cooking (Goal 7), increased household economy (Goal 8), climate change through carbon sequestration (Goal 13), forest conservation (Goal 15), and partnerships with relevant institutions (Goal 16). In order to achieve SDGs, PFM could be viewed as an integral part of government development strategies, which needs sectoral coordination and integration of relevant policies.     

资源型城市的“无废城市”建设模式探讨

资源型城市在我国经济发展大局中地位重要而特殊、历史贡献突出,城市发展的生命周期特征和物质代谢的"大进大出"特征明显,固体废物(以下简称固废)治理问题积弊已久、复杂多变。如何建设"无废城市"模式的资源型城市,是当前城市可持续发展和"无废城市"实践亟待破解的难题。本文研究分析了2017年我国资源型城市固废产生、贮存、综合利用、处置环节及管理制度体系建设的主要问题,并从制度设计、产业转型、分类利用、标准建立四个方面提出了"无废"资源型城市建设的政策建议。根据资源型城市所处生命周期发展阶段的不同,提出了基于固废"产、存、用、置、销"的存量、流量挂钩约束的发展模式。同时提出以下建议:快速成长期城市应从产业体系构建、空间布局及准入条件着手控制固废增量;平稳成熟期城市应发展完善高值化资源综合利用产业体系和制度体系;枯竭衰退期城市应注重挖掘和开发存量固废的资源价值;再生发展期城市应加强多源废物协同处置利用产业体系建设。本研究可为资源型城市的"无废城市"建设提供模式参考和政策建议。     

高水无机材料防灭火性能影响因素研究与实践*

为进一步揭示高水无机材料抑制煤自燃机理,将其更好地应用于煤矿防灭火领域,开展高水无机材料流动渗透性能实验与高水无机材料抑制煤堆自燃实验,研究不同水灰比和不同空隙率条件下高水无机材料浆液流动渗透规律和高水无机材料浆液煤堆自燃降温规律。结果表明:高水无机材料浆液的水灰比和煤块间的间隙宽度对其流动渗透性能有显著影响,煤堆不同径向距离处的温度均呈现出开始迅速降低、之后缓慢降低的2个降温阶段。三河尖矿防灭火工程实践应用表明水灰比28∶1的高水无机材料浆液有较好的防灭火效果。     

基于机器学习的恐怖袭击事件后果预测方法研究

恐怖袭击事件通常会造成严重的人员伤亡、财产损失和社会影响,针对在不同场景下发生恐怖袭击所造成的后果进行预测是目前应对恐怖袭击事件急需解决的问题之一。利用多源数据,首先基于随机森林算法对恐怖袭击事件是否造成死伤进行分类预测,进而基于岭回归算法预测事件造成的具体死伤人数。研究结果表明:随机森林在测试集上对有死伤事件的召回率达到0.85,岭回归预测死亡和受伤人数的平均绝对误差分别小于1人和2人。研究结果可为反恐资源配置优化、预防恐怖袭击事件和减少其造成的损害提供辅助决策支持。