Enhanced uranium bioleaching high-fluorine and low-sulfur uranium ore by a mesophilic acidophilic bacterial consortium with pyrite

The high level of fluorine and low sulfur in the ore could significantly undermine the bioleaching effectiveness. Here, a strategy to improve the bioleaching efficiency by introducing fluoride-resistant mesophilic eosinophils coupled with pyrite supplement was investigated in a bioleaching system with such ore. The results of column and heap bioleaching showed that 89.25% and 90.40% of uranium were recovered with the consortium and pyrite addition, which increased the uranium leaching rates by 13.22% and 8.96% as compared with the sulfuric acid leaching. Hence, it provides a method to improve uranium bioleaching efficiency of the high-fluorine and low-sulfur uranium ore by the consortium adding pyrite.

     

吡嗪类化合物的合成及其抗血小板凝集活性测试

为提高川芎嗪的抗血小板凝集活性,分别以不同的二胺、2,3-丁二酮和硫辛酸为起始原料,采用溴代、水解、环化、氧化、氢化、取代等反应,通过四条路线合成了7个川芎嗪衍生物,其结构经1H NMR、13C NMR及ESI-MS确证。采用Born比浊法初步测试了化合物的体外抗血小板凝集活性,结果显示,化合物1(IC50=0. 26mmol/L)、2(IC50=0. 27mmol/L)和7(IC50=0. 21mmol/L)对由二磷酸腺苷(ADP)诱导的血小板凝集具有一定的抑制活性,优于先导化合物川芎嗪(IC50=0. 49mmol/L)。因此,在不改变川芎嗪药效团的前提下对其进行不同程度的环化,能明显提高川芎嗪的抗血小板凝集活性,此研究为后期化合物的结构修饰提供了一定的参考价值。     

CRBN调节剂Avadomide的合成工艺优化

Avadomide是处于Ⅱ期临床阶段用于治疗晚期实体瘤的潜在药物,本文对其合成工艺进行了研究,并对重要中间体的合成工艺进行了优化。以3-硝基邻苯二甲酰亚胺为起始原料,依次经开环、霍夫曼降解、环化、酯的氨解反应、氢氧化钯/碳加氢还原反应得到Avadomide,总收率为46.9%,产物结构经~1H NMR、~(13)C NMR和HRMS表征,纯度经HPLC检测为99.5%。优化后的工艺路线具有反应条件温和、后处理简单、产率高、可操作性强等特点,更适合Avadomide的工业化生产。     

Nonlinear Evolution of Lower-Hybrid Drift Instability in Harris Current Sheet

We perform 2.5-dimensional particle-in-cell simulations to investigate the nonlinear evolution of the lower hybrid drift instability (LHDI) in Harris current sheet. Due to the drift motion of electrons in the electric field of the excited low hybrid drift (LHD) waves, the electrons accumulate at the outer layer, and therefore there is net positive charge at the inner edge of the current sheet. This redistribution of charge can create an electrostatic field along the z direction, which then modifies the motions of the electrons along the y direction by E×B drift. This effect strongly changes the structure of the current sheet.     

Numerical Simulation of Solitary Kinetic Alfvén Waves

Using the two-fluid model in the case of α〉〉1 （α= β/2Q, β is the ratio of thermal pressure to magnetic pressure, and Q = me/mi ）, we numerically investigate the interactions between two solitary kinetic Alfvén waves （SKAWs） and between an SKAW and a density discontinuity. The results show that the two SKAWs would remain in their original shapes and propagate at their initiating speeds, which indicates that SKAWs behave just like standard solitons. The simulation also shows that SKAWs will reflect and refract when crossing a discontinuity and propagating into a higher density region. The transmission wave is an SKAW with increasing density, and the reverberation is a disturbance with lower amplitude.     

用户需求行为对互联网动力学整体特性的影响

由Internet构成的复杂网络的动力学特性主要受到用户需求行为的影响,具备时域的统计规律性. 通过对区域群体用户需求行为的时域实验统计分析,发现用户对Web网站的访问频度及其生成的二分网络的入度分布也呈现幂律分布和集聚现象,其幂指数介于1.7到1.8之间. 建立了虚拟资源网络VRN和物理拓扑网络PTN双层模型,分析了双层模型映射机理,并对网络用户需求行为进行建模. 虚拟资源网络VRN对物理拓扑网络PTN映射过程的不同机理,模拟了Internet资源网络到物理网络的不同影响模式. 幂律分布的用户需求特性会 关键词： 复杂网络 无标度拓扑 用户需求 相变     

Na_2分子X~1Σ_g~ ,A~1Σ_u~ 和B~1Π_u态的势能函数

使用SAC/SAC-CI方法,利用6-311 g,6-311g**及cc-PVTZ等基组,对Na2分子的基态(X1Σg )、第一激发态(A1Σu )和第二激发态(B1Πu)的平衡结构和谐振频率进行计算.通过对3个基组的计算结果的比较,得出6-311g**基组为3个基组中最优基组的结论;使用6-311g**基组,分别利用SAC的GSUM(Group Sum of Operators)方法对基态(X1Σg ),SAC-CI的GSUM方法对激发态(A1Σu )和(B1Πu)进行单点能扫描计算,用正规方程组拟合Murrell-Sorbie函数,得到相应电子态的完整势能函数.用得到的势能函数计算与基态(X1Σg ),第一激发态(A1Σu )和第二激发态(B1Πu)相对应的光谱常数(Be,αe,ωe和ωeχe),结果与实验数据基本吻合.     

Precisely Controlled Multidimensional Covalent Frameworks: Polymerization of Supramolecular Colloids

Rapid and selective removal of micropollutants from water is important for the reuse of water resources. Despite hollow frameworks with specific functionalized porous walls for the selective adsorption based on a series of interactions, tailoring a stable shape of nanometer- and micrometer-sized architectures for the removal of specific pollutants remains a challenge. Here, exactly controlled sheets, tubes, and spherical frameworks were presented from the crosslinking of supramolecular colloids in polar solvents. The frameworks strongly depended on the architecture of original supramolecular colloids. As the entropy of colloids increased, the initial laminar framework rolled up into hollow tubules, and then further curled into hollow spheres. These shape-persistent frameworks showed unprecedented selectivity as well as specific recognition for the shape of pollutants, thus contributing to efficient pollutant separation.