活性粉末混凝土(RPC)槽形梁模型破坏试验研究

活性粉末混凝土 (RPC)具有高强、高耐久性以及高延展性等特点 ,因此 ,RPC在桥梁中有很好的应用前景。但是当前对RPC桥梁的设计研究很少 ,笔者根据自行研制的RPC ,设计了预应力拼装结构的槽形梁模型 ;并进行了RPC槽形梁模型的破坏试验研究 ,以验证槽形梁模型的承载力及发现设计上存在的问题。通过对模型拼装、预应力张拉及模型加载的试验现象的介绍和对试验结果的分析可知 ,破坏时主梁底部的拉应力远没有达到RPC的抗拉极限强度 ,而主梁腹板和下翼缘连接处的局部承载力不足才是主梁破坏的真正原因。最后 ,在总结裂缝发展和模型破坏的原因的基础上 ,对进一步的模型设计提出了修改意见。     

惰性气体抑制油气爆炸的机理分析及实验模拟

从经典燃烧学、化学反应动力学的基本理论出发,分析了惰性气体抑制油气爆炸的作用机理,通过试验模拟研究了惰性气体抑制油气爆炸的作用规律,为惰性气体防爆抑爆技术的工艺实施、系统设计和关键参数计算提供了依据.     

重质燃料油中主要芳烃在自然条件下的风化规律

文章在自然环境条件下对重质燃料油进行了风化模拟实验,采用气质(GC/MS)联用仪分析了重质燃料油中主要芳烃组分及其变化。结果表明:该重质燃料油中主要芳烃为苯类(C_nB)、萘(C_nN)类、菲(C_nP)类、二苯并噻吩(C_nD)类;在自然条件下,经过1周的风化,C_nB和C_0N完全损失;经过6周风化,C_1N完全损失;经过12周的风化,C_2N完全损失,3环的PAHs无明显变化。同时指出C_2D/C_2P和C_3D/C_3P的比值以及烷基化二苯并噻吩的同分异构体分布可用于区别其它油品,并且风化后变化不大,仍可较好地用于油品的鉴定。     

Urban riverbank residents’ evaluation of flood evacuation policies in Winnipeg, Manitoba, Canada

The results of a discrete choice experiment (DCE) as a part of a survey among the urban riverbank residents on the Red River in Winnipeg, Manitoba, Canada, indicated that the risk of over-dike flooding, set at 2 ft above the 1997 flood water level, was a significant determinant of both voluntary and mandatory evacuation, compared to those set at the 1996 or 1997 levels. Mandatory evacuation was more preferred over voluntary evacuation when the likelihood of flooding was at its most severe, and the opposite relationship was the case when the likelihood was low. The notification time for evacuation, suggested as 1, 2, and 4 days, proved to be an insignificant attribute, whereas the respondents indicated significant preference for full flood compensation over an offer of either 80% or 90% flood relief, irrespective of the alternatives of voluntary or mandatory evacuation.     

Response of Drinking-water Reservoir Ecosystems to Decreased Acidic Atmospheric Deposition in SE Germany: Signs of Biological Recovery

Strongly decreasing atmospheric emissions and acidic deposition during the 1990s have initiated chemical reversal from acidification in several drinking-water reservoirs of the Erzgebirge, SE Germany. We studied responses of phytoplankton, zooplankton and fish stocks in five reservoirs and at enclosure scale after experimental neutralization of 1,200 m³ of lake water. About 4 months after this treatment, diatoms and cryptomonads replaced the predominating chrysophytes and dinoflagellates. The colonization by acid-sensitive species of green algae, cryptomonads, rotifers and Cladocera (e.g. Bosmina longirostris) is explained by the occurrence of dormant stages or by survival of individuals in very low abundances. Analogous to the enclosure experiment, three reservoirs showed significantly (p < 0.01) falling trends of chlorophyll a and phytoplankton biovolume, mainly due to the decline of dinoflagellates. Picoplankton and diatoms increased slightly in two reservoirs. The zooplankton communities were dominated by rotifers and small Cladocera. Representatives of the genus Daphnia were lacking. Two reservoirs were re-colonized by zooplanktivorous fish populations of either perch (Perca fluviatilis) or sunbleak (Leucaspius delineatus). The latter exhibited extremely high fluctuating abundance and biomass and even suffered from a population crash. This natural mortality was caused by a limited food supply. Hence, severe top-down control may delay the recovery of larger zooplankton species like daphnids. Fishery management comprising the introduction of predatory fishes can help to control zooplanktivorous fish populations and to prevent their mass mortality.     

含膦磺酸基共聚物PAMPS的合成及阻垢性能研究

利用实验方法合成了含膦磺酸基共聚物PAMPS,通过正交试验评价优选出最佳合成条件,对其阻垢性能进行了评价。将含膦磺酸基共聚物PAMPS与HEDP和含膦基共聚物PCA进行了比较,结果表明,当PAMPS用量为10mg/L时,阻止碳酸钙结垢率达到83.73%,优于同等条件下HEDP与PCA阻止碳酸钙结垢率;当PAMPS用量达到3mg/L时,阻垢率达到98.32%,对硫酸钙的阻垢性能优于HEDP和PCA。同时还可看出,含膦磺酸基共聚物PAMPS对阻止碳酸钙结垢具有低剂量效应,对阻止硫酸钙结垢具有低剂量效应和溶限效应。这说明PAMPS是一种优良的阻垢分散剂。     

运行旅客列车隧道火灾模拟实验研究

笔者以相似理论为依据 ,以旅客列车卧铺车厢 1∶5的模型为研究对象 ,利用燃烧风洞提供的流场模拟列车在隧道中运行的速度场 ,在车厢模型中加入等比例的火灾载荷 ,进行了旅客列车隧道火灾模拟实验。研究了不同列车运行速度、不同列车火灾载荷、不同火源位置以及旅客卧铺车厢的不同状况下旅客列车火灾特征及火灾中烟气蔓延规律 ,提出了满足火灾救援和旅客疏散的要求 ,为隧道方案设计提供了可信的技术依据     

淮河淮南段河道沉积物中几种重金属元素模拟淋溶实验研究

研究了淮河淮南段河道沉积物中的三种重金属元素(Cr，Zn，Cu)在特定条件下的模拟淋溶响应，并同时研究了淮河淮南段河道沉积物底泥的特性及与重金属溶出性质间的关系。     

淀粉—丙烯酰胺接枝共聚物的合成及其污水絮凝实验研究

研究了在高锰酸钾 /草酸引发体系下 ,淀粉与丙烯酰胺的接枝共聚合反应 ,并将该接枝共聚物作为絮凝剂用于城市污水、造纸污水等的絮凝实验中 ,实验结果表明 ,其 CODCr去除率均略高于聚丙烯酰胺 (3 0 0万 )产品     

Sedimentation of short cylindrical pollutants with mechanical contacts

Lattice Boltzmann method and elastic particle collision model were used to investigate the sedimentation of short cylindrical pollutant particles with mechanical contacts for varying bulk number density ε and terminal Reynolds number ReT. The corresponding experiments were performed as a comparison. The clusters of pollutant particles with an inverted “T” structure were observed, the pollutant particles for high ε and large ReT scattered wider than that for low ε and small ReT. The sedimentation velocities increased suddenly at the initial stage, then decreased drastically, after that swayed around and approached to a steady value. The time to steady state did not depend on ε and ReT. The effect of particle interactions was to hinder the average sedimentation velocity, and hindrance was directly proportional to ε. The orientation distributions of pollutant particles depended on ReT and ε, especially on the former. Both the standard deviations of vertical and horizontal velocity, the former was larger than the latter, were nearly independent on ε and ReT.