特长公路隧道火灾烟气沉降特性对人员疏散影响的研究*

为研究特长公路隧道火灾烟气沉降对人员疏散安全的影响,通过数值模拟方法,对0,1.0,1.5 m/s和临界风速值4种不同纵向通风风速下隧道火灾烟气沉降特征进行研究,并分析不同风速下烟气沉降对人员疏散的影响。研究结果表明:在无纵向风时,烟气沉降现象较为明显,烟气下沉造成的不均匀烟气温度、能见度分布,提前终止人员疏散的进行;随着纵向风速的增加,沉降现象仍存在,但沉降点后移,对人员疏散的影响减小;在1.5 m/s的纵向通风条件下,火源下游500 m范围内烟气基本不发生沉降且能维持分层,此时几乎不影响火灾下游人员疏散。在实际应用中,火灾初期可先以1.5 m/s的分层风速值进行通风,待下游人员疏散后,再施加临界风速加快烟气排出。研究结果可为特长公路隧道火灾防治和疏散救援提供参考。     

地下水中氯代烃污染原位生物修复精细模拟研究

原位生物修复技术是修复地下水中挥发性氯代烃（VCHs）污染的重要手段之一.精细模拟修复过程是实现高效修复的关键.然而以往多数模拟VCHs修复过程的研究并未全面考虑VCHs自然衰减性质,势必会造成预测误差.因此,本研究针对当前VCHs原位生物修复模型的局限性,提出考虑VCHs自然衰减性质的原位生物修复Monod-Natural attenuation（M-Na）模型.该模型主要将自主开发的M-Na模型的源代码以用户自定义反应模块的形式嵌入到RT3D中.通过注入乳酸提供氢气进行原位生物修复含水层中四氯乙烯（PCE）污染,验证M-Na模型的精确性,并分析了修复过程参数变化（包括乳酸的注入浓度和速率）对修复效果的影响.算例分析结果表明,VCHs的自然衰减作用可以将修复产物乙烯（ETH）浓度提高10%左右,这在VCHs污染修复模拟过程中不可忽略;同时算例中乳酸的最佳注入浓度为30 mg·L^-1,最佳注入速率为200m³·d^-1.本研究成果有望为地下水VCHs污染原位生物修复精细模拟及高效修复提供模型参考.     

CuSnZr三元催化剂应用于NTP强化催化脱硫过程的特性

为高效地在低温下处理大量低浓度电解铝烟气, 采用浸渍法制备了Sn Zr型金属氧化物并添加Cu作为助剂的催化剂, 并首次测试了它在低温等离子体(NTP)技术上的脱硫效果, 结果表明负载了20wt% Cu老化温度为40℃的催化剂表现出最佳的脱硫性能.并对强化之后的催化剂进行了表征, 与新鲜的催化剂对比, X射线衍射分析(XRD)结果表明放电对催化剂晶型基本不产生影响; 扫描电子显微镜(SEM), 氮吸附和脱吸(BET)表明放电会使催化剂的吸附脱附能力与孔道结构有较大提升; X射线光电子光谱(XPS)也表明放电会使催化剂表面元素价态变化, 从而使其氧化还原性能改变, 反应路径发生偏向; 催化剂性能理论计算表明铜含量的上升会导致催化剂能带结构改变, 更好利用于激发气体.     

不同氧化还原条件下土壤中Cd/Zn/Cu共运移特征及数值模拟

以重金属离子镉（Cd）、锌（Zn）、铜（Cu）为研究对象,通过室内土柱混合置换实验和数值模拟方法,分析了5种不同氧化还原电位（E_h）对Cd、Zn、Cu在土壤中运移的影响.结果表明,不同E_h下,Cu的竞争吸附能力均大于Cd和Zn,移动性较小;并产生了“滚雪球效应”,导致出流液中Cd和Zn的浓度大于输入浓度.与原土相比,E_h的增加或降低均促进了Zn、Cd的迁移速率,但对实验周期内回收率的影响不同;E_h的增加促进了Cu的迁移.两点非平衡模型（TSM）和单点非平衡吸附模型（OSM）较好地模拟了重金属的迁移,且进一步表明了土壤对重金属的吸附受吸附反应速率的限制（f<0.7）.在复合污染土壤评价和防治中,不仅要考虑E_h的影响,还要关注由竞争吸附所产生的浓度叠加效应,避免低估重金属的污染风险.     

战斗部飞行可靠性评估方法研究

目的 解决高可靠、小子样战斗部飞行可靠性评估时样本量不满足标准要求的问题。方法 通过对战斗部结构功能分析,建立包含壳体强度、主装药安定性及主装药正常起爆等单元的可靠性框图,并利用L-M法对战斗部系统进行可靠性评估。首先利用基准设计许用值的安全系数法将应力强度干涉模型与安全系数进行结合,对壳体强度可靠性进行评估;然后结合战斗部试验数据,利用最大熵试验法,在小样本下评估战斗部主装药安定性及正常起爆的可靠性;最后,将各单元的可靠性数据转化为成败型数据进行分析,利用L-M法,结合战斗部整机试验数据,开展战斗部飞行可靠度评估。结果 分别计算了小子样下战斗部壳体和装药安定性及正常起爆的可靠度,并将其转换为等效成功数和等效失败数,结合战斗部试验打靶等可靠性信息,综合评估了战斗部飞行可靠度。结论 充分利用战斗部在研制阶段的试验信息进行评估,减少了样本量,解决了战斗部可靠性高、样本量小的评估难题。     

车用高分子材料不同地区户外曝晒试验相关性研究

目的将3种高分子材料以及3种车用外饰材料分别投放在中国海南琼海和美国佛罗里达州2种典型湿热环境中进行户外曝晒试验,研究气候相似的2种地区的试验相关性。方法通过测试相同时间间隔下不同材料在2处试验场曝晒过程中的黄变程度,表征材料的老化现象。采用斯皮尔曼等级相关系数的统计方法,研究材料在2个地区相同时间节点的试验结果的相关性,并利用时间同轴的作图方法比较2个地区严酷度的差异。结果琼海与佛罗里达州2个地区在各个时间节点的相关系数接近于1,且在材料黄变方面呈现一定比例关系。结论琼海和佛罗里达州2个地区的试验结果呈现出较好的相关性,且严酷度比值约为琼海︰佛罗里达=1︰1.19。     

大红丙烯酸油漆着色剂替代及其综合利用研究

清洁生产与资源综合利用是人们持续研究的课题,笔者在大红丙烯酸油漆着色剂"颜料红GL"替代"镉红颜料"中,开展了颜料红GL随温度、时间变化与热塑性丙烯酸树脂、有机硅助剂、二甲苯最佳浓度配比,确保着色效果及其资源综合利用等一系列试验,实现了年综合利用工艺冲洗水25.6万吨,减排CODcr 218.24吨、总镉:油漆中8031.5吨,废水中0.41吨、固废中0.088吨,提高了产品市场竞争率。     

Quantitative Determination of Rarity of Freshwater Fishes and Implications for Imperiled‐Species Designations

Abstract: Conserving rare species and protecting biodiversity and ecosystem functioning depends on sound information on the nature of rarity. Rarity is multidimensional and has a variety of definitions, which presents the need for a quantitative classification scheme with which to categorize species as rare or common. We constructed such a classification for North American freshwater fishes to better describe rarity in fishes and provide researchers and managers with a tool to streamline conservation efforts. We used data on range extents, habitat specificities, and local population sizes of North American freshwater fishes and a variety of quantitative methods and statistical decision criteria, including quantile regression and a cost‐function algorithm to determine thresholds for categorizing a species as rare or common. Species fell into eight groups that conform to an established framework for rarity. Fishes listed by the American Fisheries Society (AFS) as endangered, threatened, or vulnerable were most often rare because their local population sizes were low, ranges were small, and they had specific habitat needs, in that order, whereas unlisted species were most often considered common on the basis of these three factors. Species with large ranges generally had few specific habitat needs, whereas those with small ranges tended to have narrow habitat specificities. We identified 30 species not designated as imperiled by AFS that were rare along all dimensions of rarity and may warrant further study or protection, and we found three designated species that were common along all dimensions and may require a review of their imperilment status. Our approach could be applied to other taxa to aid conservation decisions and serve as a useful tool for future revisions of listings of fish species.     

How robust is public support for unilateral climate policy?

Most governments emphasize the need for reciprocal (“give and take”) international commitments in global climate policy. Nonetheless, existing public opinion polls indicate strong support by individual citizens for unilateral climate policies as well. This raises the question of whether governments could, without risking electoral punishment, afford to pursue more ambitious unilateral climate policies, or whether surveys may have overestimated support for unilateralism due to measurement problems. Based on conjoint and framing experiments embedded in representative surveys in the world's two largest democracies, India and the United States, we engage in a critical re-assessment of earlier survey results. We find robust public support for unilateral climate policy in both countries. Such support declines with increasing costs and increases with growing co-benefits and problem solving effectiveness. We also find, however, that policy conditionality and possible institutional design mechanisms against free-riding by other states (which make the policy “less unilateral” by providing for reciprocation) play no significant role when citizens form their preferences with respect to climate policy. Neither is public support affected by whether policies focus on adaptation (which limits benefits to the investing country) or mitigation (which benefits all countries globally). Overall, these findings suggest that, in view of very slow progress in global climate policy, governments of rich and poor countries could politically afford to push ahead with more ambitious unilateral climate policies.     

大吨位预应力锚具组装件锚固性能足尺试验

广州西塔节点层系采用大直径体外预应力拉索直接对钢管柱施加楼层平面内方向的体外预应力.选取3根φ7×199的预应力锚具组装件进行了50次周期荷载试验及静载锚同性能足尺试验.采用两台YC-1350型液压千斤顶同步顶推箱梁对预应力试验索进行张拉,测定拉索的周期载荷性能、静载锚同性能、拉伸弹性模量以及极限拉力时的总应变和锚杯与锚板间相对位移,考核锚具拉伸时锚固情况、拉伸过程及卸载后锚具的变形情况.结果表明,经过50次循环加载后试验索均无断丝,破断荷载超过12151kN,其他各项指标也均符合要求,因而能保证广州西塔体外预应力设计的安全性.