类铀矿岩材料制备及氡扩散系数测定的实验研究

扩散过程是主导氡在铀矿岩中运移与析出的主要方式。铀矿原岩辐射较大且取样困难,不利于开展有关室内实验。为了解决以上问题,依据相似理论,以某花岗岩为原型,选取石英砂、铀尾砂、水泥、精铁粉和微硅粉等为原材料,制备了3种不同材料配比的圆柱形类铀矿岩试样,并测定了原型和试样的物理力学参数;然后采用密闭腔体法测量了原型和试样在不同包裹方式下的累积氡浓度,推导氡的扩散性能参数的计算公式,通过计算获得了原型和试样的氡扩散长度和扩散系数。实验结果表明:花岗岩原型与所制备的类铀矿岩的颗粒密度、抗压强度、抗拉强度、内聚力和内摩擦角相似比的均值分别为1.09∶1、3.93∶1、4.28∶1、3.47∶1和1.00∶1;花岗岩原型的扩散系数为0.146×10^-6m²·s^-1,类铀矿岩的扩散系数介于0.114×10^-6～0.594×10^-6m²·s^-1之间,两者的相似比介于0.25∶1～1.28∶1之间。研究认为所制备的试样3在一定程度上可用来模拟花岗岩型铀矿岩,以满足室内实验的需求。     

对精神病院病房楼电气设计的探讨

介绍精神病院病房楼在照明、视频安防监控等几个方面的电气设计．并指出与普通病房电气设计存在的不同之处。     

Development of the Analysis of Fecal Stanols in the Oyster Crassostrea gigas and Identification of Fecal Contamination in Shellfish Harvesting Areas

The objective of this work was to study the effects of washing and purification steps on qualitative and quantitative analysis of fecal stanols in the oyster Crassostrea gigas using either single or a combination of lipid purification steps on silica gel or aminopropyl bonded silica gel (NH₂) or a washing step. Among the three analytical pathways compared, the two including water extraction or NH₂ purification did not lead to higher recoveries and decreased repeatabilities of extractions compared to the single purification on silica gel. This latter led to similar recoveries (ca. 80 %) and repeatabilities (ca. 10 %) for both spiked standards (coprostanol and sitostanol). This analytical pathway has been applied to oysters collected in a harvesting area in Brittany (France) where fecal contaminations are important and allowed to quantify eight stanols in oysters. The relative proportions of fecal stanols of these oysters were combined with principal component analysis in order to investigate the usefulness of their stanol fingerprints to record a fecal contamination and to distinguish its source between human, porcine and bovine contaminations. Oysters non-fecally contaminated by Escherichia coli did not present specific stanol fingerprints while oysters fecally contaminated had a bovine fingerprint, suggesting a contamination of these samples by bovine sources. As a consequence, the method developed here allows the use of stanol fingerprints of oysters as a microbial source tracking tool that can be applied to shellfish harvesting areas subjected to fecal contaminations in order to identify the different sources of contamination and improve watershed management.     

铁矿球团生球的固结机理及强化途径

通过生球强度破坏机理分析,得出通过对造球原料进行润磨可以有效的增大晶粒间的范德华力,增加生球的机械强度,添加能够通过范德华力、静电力、氢键、化学键、配位键等与铁矿颗粒表面发生作用的粘结剂也可以有效地提高生球的机械强度;提高球团的爆裂温度的有效方法是均衡球团表面气化和内部扩散作用,均衡球团表面气化和内部扩散作用的主要措施是降低球团表面气化的速度,使表面扩散速度减小,添加具有亲水基的有机粘结剂和膨润土可以降低自由水或毛细水的扩散速度,提高球团的爆裂温度;通过对造球原料的改性对生球的强度的提高是有限的,添加有机粘结剂或复合粘结剂强化生球强度仍然是今后发展的一个重要方向。     

浅析某锌锡硫化矿重选前的工艺改进

从某锌锡硫化矿的原选矿工艺分析入手,分析了其重选前选矿工艺存在的主要问题,提出了改进措施。经分析研究,改进后将获得较好的选别指标及经济效益。     

破口事故比例模拟中安全壳破口源项参数评估研究

采用基于破口总焓相似、强迫射流及浮力羽流流场相似及传热传质过程相似的多约束分析体系,归纳与质能源项相关的传热传质过程、耗散过程以及自然循环过程的时间尺度,确定模拟实验源项满足的各种模拟工况所必须遵循的设计约束条件。分析表明,自然循环过程时间常数是约束不同物理过程最重要的基础参数,也是模拟装置设计的基本约束参数。给出适用于确定安全壳破口源项试验参数的计算关系式,用于计算获得试验装置的几何参数和试验边界条件。     

微波消解-电感耦合等离子体原子发射光谱法测定华阳川多金属矿石中铌

华阳川铀铌铅多金属矿石中的金属离子被硅晶核包裹,不易浸出,且铌元素易水解沉淀,这些均给测定样品中铌带来了难题。实验采用氢氟酸、硝酸、酒石酸混酸体系以微波消解法处理样品,以Nb 309.418 nm为分析谱线,建立了电感耦合等离子体原子发射光谱法测定华阳川铀铌铅多金属矿石中铌的方法。确定微波消解的程序为:0~30 min从室温达到180 ℃,30～60 min从180 ℃到200 ℃,60～90 min鼓风降温。实验表明:铌的质量浓度在0.10～2.00 μg/mL范围内与其发射强度呈线性关系,线性相关系数为0.999 946,方法检出限为0.002%。因样品中主成分二氧化硅绝大部分在样品制备时已和氢氟酸反应生成四氟化硅逸出,而样品溶液中其他共存元素的质量浓度均不大于80 μg/mL,故基体效应可忽略。采用实验方法测定铌质量分数为0.030 2%~0.189%的华阳川多金属矿石样品,6次平行测定结果的相对标准偏差(RSD)为3.1%~3.9%。考虑到铌钽元素通常伴生,元素性质十分相近,且矿性高度相似,所以实验采用有铌认定值的钽矿石标准物质为测定对象,按照实验方法进行测定,测得结果与认定值基本一致。采用国家标准方法GB/T 17415.2—2010和实验方法进行方法对照,结果表明,二者对华阳川多金属矿石样品中铌的测定结果基本一致。     

Iron Ore Sintering: Process

Sintering is a thermal agglomeration process that is applied to a mixture of iron ore fines, recycled ironmaking products, fluxes, slag-forming agents, and solid fuel (coke). The purpose of the sintering process is manufacturing a product with the suitable characteristics (thermal, mechanical, physical and chemical) to be fed to the blast furnace. The process has been widely studied and researched in the iron and steelmaking industry to know the best parameters that allow one to obtain the best sinter quality. The present article reviews the sintering process that the mixture follows, once granulated, when it is loaded onto the sinter strand. There, the sinter mixture is partially melted at a temperature between 1300-1480°C and undergoes a series of reactions that forms the sinter cake to be loaded into the blast furnace to produce pig iron.     

Particulate matter chemical component concentrations and sources in settings of household solid fuel use

Particulate matter (PM) air pollution derives from combustion and non‐combustion sources and consists of various chemical species that may differentially impact human health and climate. Previous reviews of PM chemical component concentrations and sources focus on high‐income urban settings, which likely differ from the low‐ and middle‐income settings where solid fuel (ie, coal, biomass) is commonly burned for cooking and heating. We aimed to summarize the concentrations of PM chemical components and their contributing sources in settings where solid fuel is burned. We searched the literature for studies that reported PM component concentrations from homes, personal exposures, and direct stove emissions under uncontrolled, real‐world conditions. We calculated weighted mean daily concentrations for select PM components and compared sources of PM determined by source apportionment. Our search criteria yielded 48 studies conducted in 12 countries. Weighted mean daily cooking area concentrations of elemental carbon, organic carbon, and benzo(a)pyrene were 18.8 μg m^?3, 74.0 μg m^?3, and 155 ng m^?3, respectively. Solid fuel combustion explained 29%‐48% of principal component/factor analysis variance and 41%‐87% of PM mass determined by positive matrix factorization. Multiple indoor and outdoor sources impacted PM concentrations and composition in these settings, including solid fuel burning, mobile emissions, dust, and solid waste burning.