零价铁降解氯代有机污染物的QSPR研究

利用密度泛函理论B3IYP/6-31G(d)水平计算氯代有机污染物绝热电子亲合能(EAad)、垂直电子亲合能(EAvert)及C-Cl键键离解能(BDE),据此研究零价铁对该类化合物脱氯降解的定量结构-性质关系(QSPR).结果表明,描述符EAad和BDE所建QSPR模型效果均较好,同时EAad可以很好地体现还原过程,BDE则对于降解途径预测具有较大价值.     

青藏工程走廊水环境安全保护等级区划研究

采用模糊数学综合评判法和突变级数法对青藏工程水环境安全的保护等级进行分区评价与研究,结果表明:青藏工程走廊带沿线水环境分为一级、二级和三级保护区3个区域,其中一级区范围为青藏高速公路拉萨—安多段,二级区范围为青藏高速公路安多—茶错段,三级区范围为青藏高速公路茶错—格尔木段;青藏工程走廊水环境安全保护路段共计408.92 km,安全保护等级高,占路线全长的35.56%。建议拉萨—安多全段,以及安多—茶错段部分路(桥)面通过工程措施和非工程措施相结合的方式实现路(桥)面径流污染控制,有效降低路(桥)面径流对走廊带水环境的影响。     

磁性氧化石墨烯和磁性竹炭对Cr（Ⅵ）的吸附

制备了两种磁性碳基材料——磁性氧化石墨烯（MGO）和磁性竹炭（MBC）,并将其用于模拟含Cr（Ⅵ）废水的吸附。采用SEM,BET,FTIR技术对吸附剂进行了表征。表征结果显示：MBC具有与MGO相似的薄片层结构,且MBC的BET比表面积更大（为32.872 6 m²/g）,可为Cr（Ⅵ）提供大量的吸附位点。实验结果表明：向100 mL废水中加入20.0 mg吸附剂,在废水pH为1.0、吸附温度为30 ℃、初始Cr（Ⅵ）质量浓度为10.0 mg/L的条件下,MGO和MBC的平衡吸附时间分别为50,70 min,平衡吸附量分别为37.7,49.7 mg/g,吸附平衡时的Cr（Ⅵ）去除率分别为75.4%和99.4%;两种磁性材料对Cr（Ⅵ）的吸附均很好地符合Langmuir等温吸附模型;在酸性介质中,MGO和MBC的表面基团与HCr₂O₇^-和Cr₂O₇^2-之间有氢键作用。     

坝上高原栗钙土退化的一些特征

坝上高原生境脆弱与人为不合理活动的叠加影响,导致票钙土退化。表现为土壤代换量降低,养分含量减少,有机复合体破坏;松结合态、稳结合仓和紧结合态腐殖质下降,其下降率依序为21％～34％、44％～55．5％和5％～62％。     

淄博某热电厂粉煤灰双免砖的研制

研究了粉煤灰的用量、成型水分、粘结剂的种类及用量、外加剂的种类及用量、养护时间等因素对粉煤灰双免砖的影响,探讨了粘结剂的作用机理.     

基于蝴蝶突变理论的企业安全生产保障系统危险程度四维分析模型

利用蝴蝶型突变建立人、物、管理、环境安全生产保障模型,人、物、管理、环境的权重与四个控制变量各自相乘,就可能构成了更具有代表和全面含义新突变级数。新突变级数乘于各自单位向量,得出四维控制变量,为在四维空间上分析企业的安全生产危险程度的临界点提供了新的思路。建立蝴蝶型突变理论的在安全决策模型,将企业的安全生产危险程度分为：理想的安全区域;危险区域;相对的安全区域,蝴蝶型突变理论能够揭示企业的安全状况。     

Enhancement of phenanthrene adsorption on a clayey soil and clay minerals by coexisting lead or cadmium

Phenanthrene is commonly present together with heavy metals at many contaminated sites. This study investigated the influence of coexisting lead (Pb²⁺) or cadmium (Cd²⁺) on phenanthrene adsorption on soils. Batch experiments were conducted under different geochemical conditions including pH, mineral structure, organic matter content, and varying amounts of heavy metals. The results showed that the presence of heavy metals in solution at a fixed pH of 5.8 ± 0.1 enhanced phenanthrene adsorption, the extent of which was closely related to the concentrations and the electro-negativity of the metals. The enhancement on phenanthrene adsorption was positively correlated to the amount of adsorbed metals. Although Cd²⁺ is a softer Lewis acid, Pb²⁺ displayed a more significant effect as it was adsorbed to a greater extent on the soil surfaces. Thus, density of cation accumulation appears to be more influential than metal softness in enhancing phenanthrene adsorption. Moreover, with a portion of organic matter removed by heating at 550 °C, there was a stronger enhancement of phenanthrene adsorption by coexisting Pb²⁺, indicating an increasingly dominant mechanisms associated with Pb²⁺ at a lower organic matter content. Similar enhancement phenomenon was observed on bentonite and kaolinite, probably resulting from the cation-π bonding between the adsorbed soft metal cations and the aromatic ring of phenanthrene in solution. The desorption experiments further suggested that the bonding of phenanthrene adsorption was strengthened in the presence of Pb²⁺ and that a larger proportion of adsorbed phenanthrene remained on the soils (residual fraction) even after sequential methanol extractions. Further spectroscopic analyses and surface characterization are required to provide direct evidence of the formation and relative significance of cation-π bond for phenanthrene adsorption.     

烯酮还原酶基因的克隆与优化表达

烯酮/酯还原酶可以专一性地还原烯酮/酯中的碳碳双键,并引入两个手性中心,是手性化合物生物催化合成的重要酶类之一;在使用烯酮/酯还原酶进行全细胞手性分子生物催化合成中,其他还原酶的存在常导致副反应的产生.为研究烯酮/酯还原酶的理化性质、底物的专一性、产物的手性特点等,需要经过纯化的烯酮/酯还原酶.为此,根据烯酮还原酶(Enoate reductase,ERs,EC 1.3.1.31)的基因序列设计引物,以丙酮丁醇梭菌(Clostridium acetobutylicum)ATCC824基因组DNA为模板,通过PCR扩增技术得到了目标酶的基因,目的片段全长为1 995 bp,共编码664个氨基酸,相对分子质量为73×103.将烯酮还原酶基因连接到pET-32a(+)上,构建表达质粒pET-32a(+)-ERs,并成功在Escherichia coli Rosetta(DE3)pLysS中表达.在摇床上优化的表达条件为:诱导温度为18℃,诱导起始时菌体D600 nm为0.6～0.8,转速为100 r/min,诱导剂IPTG浓度为0.1 mmol/L,诱导培养时间为12 h,表达的烯酮还原酶大部分以可溶性形式存在于菌体内.     

胺基修饰的大孔树脂吸附黄连素的研究

为了提高大孔吸附树脂对黄连素的吸附能力,根据黄连素结构特点,对具有苯乙烯骨架的H109树脂进行了胺基修饰.考察了胺基修饰后的特征基团、孔径和比表面积的变化,并测试了经胺基修饰后树脂对黄连素的吸附效果,确定了最佳吸附温度和初始pH.同时,对吸附过程进行吸附动力学和热力学的拟合与分析.红外扫描结果表明:胺基修饰成功,吸附过程中树脂上的胺基与黄连素分子中的醚基形成了氢键;胺基修饰后的HX树脂的孔径和比表面积有所增大,比吸附量比胺基修饰前增加7.9mg·g-1.HX树脂对黄连素的最佳吸附条件为30℃、初始pH值8.吸附过程可以采用伪二级动力学模型和Freundlich吸附等温线进行描述.     

Motor vehicle towing: An analysis of injuries in a high-risk yet understudied industry

Objectives: National fatality rates for commercial tow truck operators exceed those of other first responders who also perform traffic incident management services. The objectives of the current study are to (1) characterize causal factors associated with injuries among commercial tow truck operators engaged in roadside assistance through analysis of coded and free text data obtained from U.S. Occupational Safety and Health Administration (OSHA) investigation files, and (2) utilize supplemental data sources to analyze environmental factors for injuries in which commercial tow truck operators were struck by roadway traffic. Methods: Searches of OSHA’s online IMIS database were performed to identify investigations of incidents in which tow truck operators were injured while performing roadside assistance duties. Freedom of Information Act (FOIA) requests were submitted to obtain full investigation files for each case. Coded and narrative text analyses were performed to identify causal themes across the identified cases. Results: One-hundred and six cases of tow truck operators being killed or severely injured were identified in IMIS; 41 FOIA requests for related investigation documents were fulfilled. Two major event type themes were identified which accounted for 9 in 10 of the cases identified. These were (1) ‘struck-by’ incidents, which were primarily injuries resulting from contact with roadway traffic, rolling vehicles and equipment or other non-motorized objects; and (2) ‘caught-in or -between’ incidents, which were primarily injuries resulting from being pinned beneath and between vehicles and being caught in moving parts. Conclusions: The towing industry should provide initial and refresher safety training on vehicle loading and unloading, defensive techniques when exposed to traffic on roadways, and proper wheel chocking and braking procedures. States should include tow trucks as a first responder vehicle type in their “Move Over” laws and implement public awareness campaigns to protect all first responders, including tow truck operators.