Sedimentary record of polycyclic aromatic hydrocarbons in Lake Erhai, Southwest China

The temporal distribution of polycyclic aromatic hydrocarbons (PAHs) was investigated in a sediment core from Lake Erhal in Southwest China using gas-chromatography/mass spectrometry (GC/MS) method.The total organic carbon (TOC) normalized total PAHs concentrations (sum of US Environmental Protection Agency proposed 16 priority PAHs) ranged from 31.9 to 269 μg/g dry weight (dw),and were characterized by a slowly increasing stage in the deeper sediments and a sharp increasing stage in the upper sediments.The PAHs in the sediments were dominated by low molecular weight (LMW) PAHs,suggesting that the primary source of PAHs was low- and moderate temperature combustion processes.However,both the significant increase in high molecular weight (HMW) PAHs in the upper sediments and the vertical profile of diagnostic ratios pointed out a change in the sources of PAHs from low-temperature combustion to high-temperature combustion.The ecotoxicological assessment based on consensus-based sediment quality guidelines implied that potential adverse biological impacts were possible for benzo(ghi)perylenelene and most LMW PAHs.In addition,the total BaP equivalent quotient of seven carcinogenic polycyclic aromatic hydrocarbons (BaA,CHr,BbF,BkF,BaP,DBA and INP) was 106.1 ng/g,according to the toxic equivalency factors.Although there was no great biological impact associated with the HMW PAlls,great attention should be paid to these PAH components based on their rapid increase in the upper sediments.     

关于企业管理系统的优化建议

ERP是英文Enterprise Resource Planning（企业资源计划）的缩写,ERP企业管理系统是＂E时代＂最有效的企业管理系统,     

Arsenic removal from groundwater by acclimated sludge under autohydrogenotrophic conditions

Arsenic in the environment is attracting increasing attention due to its chronic health effects. Although arsenite(As(III)) is generally more mobile and more toxic than arsenate(As(V)), reducing As(V) to As(III) may still be a means for decontamination, because As(III) can be removed from solution by precipitation with sulfide or by adsorption or complexation with other metal sulfides. The performance of As(V) bio-reduction under autohydrogenotrophic conditions was investigated with batch experiments. The results showed that As(V) reduction was a biochemical process while both acclimated sludge and hydrogen were essential. Most of the reduced arsenic remained in a soluble form, although 20% was removed with no addition of sulfate, while 82% was removed when sulfate was reduced to sulfide. The results demonstrated that the reduced arsenic was re-sequestered in the precipitates, probably as arsenic sulfides. Kinetic analysis showed that pseudo first-order kinetics described the bio-reduction process better than pseudo second-order. In particular, the influences of pH and temperature on As(V) reduction by acclimated sludge under autohydrogenotrophic conditions and total soluble As removal were examined. The reduction process was highly sensitive to both pH and temperature, with the optimum ranges of pH 6.5–7.0 and 30–40°C respectively. Furthermore, Arrhenius modeling results for the temperature effect indicated that the As(V) reduction trend was systematic. Total soluble As removal was consistent with the trend of As(V) reduction.     

泥炭碱提取液E4/E6值表征泥炭腐殖化度及其古气候意义

采用AMS14C测年技术建立了哈尼泥炭地的年代序列,以泥炭碱提取液的E4/E6值(400nm和600nm处吸光度比值)来表征泥炭腐殖化度,并探讨其指示的古气候意义。研究结果表明:根据泥炭碱提取液E4/E6值与校正年龄的变化曲线,以及将其与哈尼泥炭400nm处吸光度直接表征腐殖化度的曲线进行对比,发现哈尼泥炭碱提取液的E4/E6值对古气候具有很好的指示意义,对全新世以来的气候突变事件以及前人研究的气候时期划分都能得到很好的对应,即哈尼泥炭碱提取液E4/E6值高,泥炭腐殖化度低,指示气候干冷,其E4/E6值低,泥炭腐殖化度高,指示气候暖湿。在今后的研究中,可结合E4/E6值来表征泥炭腐殖化度,并结合磁化率、孢粉等化学物理生物因子以及温度、湿度、水文、地质条件等其他因素来探讨泥炭腐殖化度对古气候的指示意义。     

凹凸棒石的表面修饰及对水中Cr（Ⅵ）吸附动力学和热力学的研究

以壳聚糖为生物质碳源,采用一步水热碳化法对凹凸棒石表面进行有机修饰,并采用扫描电镜(SEM)、拉曼(Raman)光谱、元素分析(EA)、X光电子能谱(XPS)、Zeta电势分析、热重分析(TGA)等对改性凹凸棒石进行表征分析.同时,通过静态吸附实验,研究了改性凹凸棒石对Cr(Ⅵ)吸附去除的性能,考察了温度对吸附性能的影响,探讨了吸附动力学和热力学规律.结果表明,改性凹凸棒石表面富含含氧基团和氨基等活性基团;对总铬的吸附行为符合准二级动力学方程;表观吸附活化能为13.4 k J·mol~(-1),表明既有静电吸附,也有配位吸附,且以静电吸附为主;对总铬的吸附等温线符合Langmuir方程.在温度为298、308、318和328 K时,最大吸附量分别为203.3、232.6、267.4和322.6 mg·g~(-1),说明改性凹凸棒石是一种新型环保高性能的除铬材料.在研究的温度范围内,ΔH~0为19.8 k J·mol~(-1),ΔG~0为-19.5~-23.7 k J·mol~(-1),ΔS~0为72.1~131.8 J·mol~(-1)·K~(-1),表明该吸附是一吸热的、自发的、熵增过程.     

蚯蚓细胞色素P450酶系对土壤中芘或苯并[a]芘的响应

以赤子爱胜蚓(Eisenia fetida)为受试生物,通过人工污染草甸棕壤微宇宙试验方法,研究了暴露于不同环境浓度芘或苯并[a]芘(添加量分别为0.12、0.24、0.48、0.96 mg·kg~(-1))污染的土壤中14 d后,蚯蚓体内细胞色素P450(CYPs)酶系,如CYPs总量、CYP1A1及CYP2C9活性的变化.结果显示,芘或苯并[a]芘暴露导致蚯蚓CYPs总量、CYP1A1及CYP2C9活性的变化不同.其中,CYPs总量与CYP1A1活性对芘的响应趋势相似:试验3 d后,0.96 mg·kg~(-1)芘导致二者都显著高于对照水平;14 d后,都显著低于对照水平;CYP1A1活性对芘的响应更为敏感.CYPs总量与CYP2C9活性对苯并[a]芘的响应趋势相似:暴露初期,苯并[a]芘最高暴露剂量(0.96 mg·kg~(-1))导致二者都显著低于对照水平;试验结束后,苯并[a]芘最低暴露剂量(0.12 mg·kg~(-1))导致二者都显著高于对照水平,最高剂量暴露导致二者都显著低于对照水平,CYP2C9活性对苯并[a]芘的响应更为敏感.因此,推断CYPs亚酶对污染物的响应具有选择性且亚酶的响应敏感度高于CYPs总量.将CYPs总量与CYP1A1活性结合,或与CYP2C9活性结合分别诊断土壤芘污染或并[a]芘污染,较为准确有效.     

TEPA调控AMP-DGDE水溶液相变吸收CO2性能及机理

相变吸收剂在降低CO₂捕集能耗方面具有较大优势,但现有吸收剂普遍存在再生性能差的问题。基于2-氨基-2-甲基-1-丙醇(AMP)的吸收剂再生性能优异,但通常难以发生相变。利用四乙烯五胺(TEPA)作为相变调控剂引入AMP-二乙二醇二甲醚(DGDE)水溶液,构建了具有良好再生性能的新型相变吸收剂AMP-DGDE-TEPA。在最佳配比下,AMP-DGDE-TEPA的吸收负荷可达0.88 mol·mol-1,其中97.6%的CO₂富集于溶液下层,下层体积仅占总体积51%。经7次吸收-解吸循环,吸收剂的吸收负荷仍能保持0.63 mol·mol-1,再生效率为71.6%。13C核磁共振结果表明,AMP与CO₂反应生成易于分解的碳酸氢盐,因而吸收剂具有良好的再生性能;而TEPA的引入可使系统中生成稳定的质子化TEPA和氨基甲酸盐。质子化TEPA和氨基甲酸盐具有高极性,可打破吸收剂原有的均相状态,促使吸收剂发生液-液相变。相比于DGDE,H₂O和极性反应产物之间具有更强的相互作用力,这些物质聚集形成CO_...     

基于等级全息建模的输油泵机组风险根源辨识*

为“挖掘”输油泵机组风险根源,降低设备预知性维护难度,结合输油泵多准则风险评价,提出1种基于等级全息建模的输油泵机组风险根源辨识方法,运用等级全息建模方法将输油泵系统分解为泵体结构、管理因素、环境因素、操作因素、技术因素、运行因素、设备安装7个子系统进行定性和定量分析。结果表明:相比危险与可操作性分析（HAZOP）、事故树分析（FTA）等传统风险辨识方法,等级全息建模（HHM）对轴承等关键部件以及压力等运行参数的监测更为深入,能够有效辨识输油泵机组高风险情景,提升输油泵的风险辨识效率。     

时间因素对钻屑瓦斯解吸指标K1值测定的影响分析

针对时间因素对钻屑瓦斯解吸指标K1测定结果的影响,采用恒温瓦斯放散试验深入分析钻屑瓦斯解吸指标K1测定理论的准确性,总结因时间因素导致K1值测定误差所带来的现场问题。研究结果表明:K1值的测定误差与时间关系密切,测定启动时间越晚,误差越大;测定启动时间由第1 min延后至第2 min,绝对误差和相对误差最大值分别增加0.081 cm3/(g·min1/2)和2.20%;高瓦斯压力条件矿井或煤层的局部高瓦斯压力区域、构造煤发育区的钻屑瓦斯解吸指标K1值测定结果偏低,测定误差偏大。研究结果可为煤与瓦斯突出预测水平的提升提供技术支撑。     

隧道救援站通风网络优化设计及人员疏散研究*

为确定铁路隧道救援站最佳通风结构,对烟道布置提出合理建议,采用计算流体力学（CFD）的方法,对铁路隧道救援站通风网络进行优化设计。同时,采用模拟计算的方法对救援站人员疏散进行模拟分析,确定救援横通道布置及防护门开度设置的合理性。研究结果表明:在同等通风参数工况设置下,采用多节点排烟竖井结构后各救援横通道流量分配更均匀,救援站压力平衡性更好,通风效率可提升15%;通过疏散模拟证实,在长560 m的紧急救援站范围内设置10条疏散横通道,横通道设1.7 m宽的逃生门能够满足疏散要求。