黑藻对镉离子的生物吸附研究

研究了黑藻对镉离子的吸附作用,考察了溶液pH、镉离子初始浓度、吸附剂用量和吸附时间等因素对吸附的影响.在选定的吸附条件下,即pH为6.0,吸附剂用量为2 g·L-1,吸附时间为120 min时,对于50 mg·L-1的Cd+溶液,黑藻对Cd+的吸附效率为96%,吸附量为24.1 mg·g-1.常温下黑藻对Cd+的吸附作用可用Langmiur、Freundlich和Dubinin-Radushkevich(D-R)等温吸附模型进行拟合,相关系数r2分别达到0.9852、0.9901和0.9982,说明吸附反应符合这三种吸附模型.     

As Doping in (Hg,Cd)Te: An Alternative Point of View

Acceptor doping of many II–VI compound semiconductors has proved problematic and doping of epitaxial mercury cadmium telluride (MCT, Hg_1−x Cd _x Te) with arsenic is no exception. High-temperature (>400°C) anneals followed by a lower temperature mercury-rich vacancy-filling anneal are frequently required to activate the dopant. The model frequently used to explain p-type doping with arsenic invokes an amphoteric nature of group V atoms in the II–VI lattice. This requires that group VI substitution with arsenic only occurs under mercury-rich conditions either during growth or the subsequent annealing and involves site switching of the As. However, there are inconsistencies in the amphoteric model and unexplained experimental observations, including arsenic which is 100% active as grown by metalorganic vapor-phase epitaxy (MOVPE). A new model, based on hydrogen passivation of the arsenic, is therefore proposed.     

Finite elements modeling of multilayers of Cr/CrN

One of the most used methods for modeling different materials and their properties has been finite elements. In this work, mechanical properties of Cr/CrN multilayer coatings have been modeled by using finite elements, varying the period of layers (1, 5, 10 and 20 bilayers) and the thickness of the films between 0.5 and , in order to determine the behavior of the system. For this model, the software ANSYS was used to carry out simulation of the indentation process. For the analysis, a conical Berkovich indenter was built. The simulation consists in generating the stress-strain curves in the charge mode for obtaining Young's modulus of the total system, including the substrate, which is made by stainless steel 304. The curves showed a tendency of increasing of Young's modulus as a function of number of layers and thickness, which means an increasing in hardness.     

Efficiency,mechanism and microbial community of Cd(II) removal by mixed bacteria enriched from heavy metals mine soil

Mixed bacteria were enriched from heavy metals mine soil for cadmium (Cd(II))-containing wastewater treatment. Batch adsorption experiment results showed that the optimal pH, temperature, initial Cd(II) concentration, and biomass dosage were 6.0, 30 °C, 20 mg/L, and 1 g/L, respectively. Living biomass exhibited better Cd(II) removal efficiency (91.97%) than autoclaved biomass (79.54%) under optimal conditions. The isotherms and kinetics of living biomass conformed to the Langmuir isotherm model and pseudo-first-order kinetic model, respectively. FTIR results implied that amine groups, hydroxyl groups and phosphoric acid play an important role in the Cd(II) adsorption process, while XRD results showed that crystalline Cd(OH)₂ and CdO were obtained. After Cd(II)-containing wastewater treatment exposure, the dominant bacteria genera included Comamonas (39.94%), unclassified_f__Enterobacteriaceae (34.96%), Ochrobactrum (14.07%), Alcaligenes (4.84%), Bordetella (2.07%), Serratia (1.04%), and Bacillus (1.01%). Function prediction showed that the abundance of metabolic genes changed significantly. This study proposes the potential application of mixed bacteria for Cd(II)-containing wastewater treatment.     

Impacts of an ATF cladding on neutronic performances of the soluble-boron-free ATOM core

This article is mainly concerned with the impacts of various accident tolerant fuel (ATF) claddings on neutronics performances of a soluble-boron-free (SBF) small modular reactor (SMR) core. There are two ATF cladding concepts which are evaluated here: (a) coating Zircaloy-4 cladding with a thin layer of Cr or Cr alloys; (b) high-strength and oxidation-resistant claddings: stainless steel and FeCrAl. Comparisons between Zircaloy-4 and ATF claddings are done in terms of the cycle length, discharge burnup, pin peaking factor (PPF), burnup reactivity, and spectral change. Moreover, the ATF claddings are also compared in view of the rim effect, neutron absorption by the cladding and He production in the cladding. In addition, a linear reactivity model is used to estimate the required U-235 enrichment so that the cycle length with ATF claddings should be equivalent to that with the reference Zircaloy-4 case. Furthermore, impacts of a selected ATF cladding are then analyzed in a centrally shielded burnable absorber (CSBA)-loaded FA in terms of PPF, burnup reactivity, and spectral change. Based on the CSBA-loaded FA analysis, a minor modification of burnable absorber loading strategy in the SBF autonomous transportable on-demand reactor module core is proposed to adopt the selected ATF cladding without compromising the core performance. The lattice calculations are done using the Monte Carlo Serpent 2 code with the ENDF/B-VII.1 nuclear library, while the 3-D multi-physics core calculations are performed using a Monte Carlo-diffusion hybrid procedure.     

电感耦合等离子体质谱法测定地质样品中的镉

采用电感耦合等离子体质谱法测定岩石、土壤、水系沉积物等地质样品中微量镉,方法简便?快速。Cd的检出限为0.0036μg/g,相对标准偏差(n=10)为0.71%,标准Cd加入回收率为94%~106%。该方法用国家一级标准物质验证,结果与推荐值相符。     

微波消解-石墨炉原子吸收法测定中药中痕量镉的研究

本文通过考察各因素对样品消解效果的影响及对石墨炉原子吸收各条件进行优化 ,建立一种快速、有效的中药中镉含量的检测方法 ,方法检出限为 0 0 1 1 9ng·mL- 1,线性范围 0 0 0 6～ 2ng·mL- 1,样品测定回收率 91 7%～ 1 0 4 3% ,结果满意     

原子吸收分光光度法连续测定锰粉中微量Fe、Pb、Sb、Ca和Cd

提出了原子吸收分光光度法测定锰粉中微量杂质（Fe，Pb，Sb，Ca，Cd）的方法。用硝酸溶解锰粉试样，在几个相同量的试液中，分别加入浓度依次递增的Fe，Pb，Sb，Ca和Cd等5种金属元素的标准溶液，再加入释放剂SrCl2溶液，用空气-乙炔火焰原子吸收分光光度法连续测定5种元素的含量。优化了仪器的测定条件，进行了相关的干扰实验。方法的回收率为97．6％～102．0％，相对标准偏差为1．8％～2．6％。     

Magnetic Field‐Enhanced Thermoelectric Performance in Dirac Semimetal Cd3As2 Crystals with Different Carrier Concentrations

The magneto‐thermoelectric figure of merit (ZT) in crystals of the topological Dirac semimetal Cd₃As₂ with different carrier concentrations is studied. The ZTs for all the crystals increase with the temperature and show maxima at high temperatures. Meanwhile, the temperatures corresponding to the ZT maxima increase with the carrier concentration. The limit to the improvement in ZT(T) at high temperature could be related to the unusual large enhancement in thermal conductivity at elevated temperatures. The bipolar effect and Dirac liquid behavior are presented as processes possibly responsible for the peculiar behavior of the thermal conductivity. Applying a transverse magnetic field initially leads to a dramatic enhancement and, subsequently, to a slight reduction in ZT for all the crystals. The maximum ZT achieved in a magnetic field increases with the carrier concentration and reaches 1.24 at 450 K in a magnetic field of 9 T for the crystal with the highest carrier concentration. It is expected that this work will be beneficial to the current interests in optimizing the thermoelectric properties of quantum topological materials.     

镉掺杂氧化亚铜薄膜的制备及其光电性能

采用一步水热法制备镉掺杂的Cu2O薄膜(Cd/Cu2O),分别探讨了制备过程中CuSO4浓度、NaOH浓度、反应时间、反应温度和CdSO4浓度对Cu2O和Cd/Cu2O薄膜光电性能的影响。结果表明,当反应釜中CuSO4浓度为0.114 2 mol/L、NaOH浓度为0.028 6 mol/L、反应时间为8 h、反应温度为90℃、CdSO4浓度分别为0 mol/L和0.571 4μmol/L时,可在基底Cu片上分别获得光电压为0.366 7 V的Cu2O样品和光电压为0.460 2 V的Cd/Cu2O薄膜样品。紫外可见吸收光谱(UV-Vis)、X射线衍射(XRD)图谱、扫描电子显微镜(SEM)和能谱仪(EDS)表征结果显示,Cu2O的禁带宽度为2.1 eV,而Cd/Cu2O的禁带宽度最小达到1.8 eV;Cd/Cu2O的择优生长面为(111)面,其衍射峰强度比Cu2O明显增强;Cd/Cu2O样品表面与Cu2O对比变得光滑,粒径由Cu2O的1.0~3.0μm减小到Cd/Cu2O的0.3~0.9μm。