铋、氧化铋、硫化铋在醋酸-硫脲中的溶解性研究

通过研究铋(Ⅲ)与硫脲络合染色,测得络合物最大吸收峰位于460nm波长处,Bi(Ⅲ)含量在0.059～5.7μg/mL范围内符合比尔定律,回归方程Y=0.0117+0.17319 X;相关系数R=0.9999;相对标准偏差RSD为2.66%;检出限为0.013μg/mL;摩尔吸光系数为3.72×104 L.mol-1.cm-1。实验结果表明,铋、氧化铋和硫化铋在醋酸-硫脲中的溶解度分别是0.077、1.347、1.245μg/mL。经比较发现铋、氧化铋和硫化铋在醋酸-硫脲中的溶解性大小是:氧化铋>硫化铋>铋。铋、氧化铋和硫化铋的回收率分别是97.4%、98.1%、96.6%。     

双诱导映射■集合范畴的L_b-余等值子和L_b-正则满态射(英文)

In this paper,it gives the definition of the category of ■-sets and bi-induced maps whose true value set is a Locale,a complete Heyting algebra.In this category it defines the L_b-monomorphisms and the L_b-epimorphisms.Especially,it gives the definition,the judgmental theorem of L_b-coequalizers.Furthermore,it defines L_b-regular epimorphisms and proves the judgmental theorem.At the end it concludes a result:the category of ■-sets and bi-induced maps is finitely cocomplete.     

层次闭包空间中分子网的收敛及其应用

研究层次闭包空间中分子网的收敛理论及其在连续性、分离性和紧性理论中的应用.     

热塑性聚氨酯共混物的硬度与冲击性能的关系北大核心CSCD

选取了2种分子组成相同硬度不同的热塑性聚氨酯(TPU),将二者共混后得到了不同硬度的TPU共混物,探究了TPU共混物的硬度与冲击性能的关系。通过落球冲击试验、感压纸测试和冲击前后样品表面温度测试对TPU共混物的冲击性能进行表征。当样品的硬度越低时,峰值冲击力越小,冲击持续时间越长,冲击时的最大应变越大,冲击时样品的受力面积增大,对应的冲击时的峰值应力值减小。不同硬度样品的能量耗散比差别不大,但随硬度降低呈现小幅度上升趋势。冲击后的样品表面温度较冲击前有所上升,说明样品通过热的形式耗散了部分能量,各硬度样品的温度差值较为接近,这与不同硬度样品的能量耗散比的变化规律是相似的。所有样品均具有较高的能量耗散比,TPU能耗散大部分冲击能量,具有良好的抗冲击性能。     

CoFe2O4 nanoparticles anchored on waste eggshell for catalytic oxidation of florfenicol via activating peroxymonosulfate

Eggshell-loaded CoFe₂O₄ catalyst was synthesized via a convenient hydrothermal method during our work, then the surface morphology and elemental composition of the composites were systematically investigated. Performance of CoFe₂O₄/eggshell-activated peroxymonosulfate (PMS) system was evaluated by selecting florfenicol (FF) as the model pollutant, and effects of operating parameters and water matrices on the FF removal efficiency in this system were investigated. In addition, main radicals involved in FF degradation were identified by EPR tests and radical quenching experiments, and possible mechanism was proposed. The reduction of toxicity during FF degradation was confirmed, and in combination with HP-LC tests, it was found that dehalogenation and defluorination were effectively carried out during FF degradation. In addition, the prepared CoFe₂O₄ polyvinylidene fluoride (PVDF) membrane effectively improved the stability of the material and reduced the precipitation of metals.     

Paclitaxel‐Loaded β‐Cyclodextrin‐Modified Poly(Acrylic Acid) Nanoparticles through Multivalent Inclusion for Anticancer Therapy

A nanoassembled drug delivery system for anticancer treatment, formed by the host–guest interactions between paclitaxel (PTX) and β‐cyclodextrin (β‐CD) modified poly(acrylic acid) (PCDAA), is successfully prepared. After such design, the aqueous solubility of PTX is greatly increased from 0.34 to 36.02 μg mL^?1, and the obtained PCDAA‐PTX nanoparticles (PCDAA‐PTX NPs) exhibit a sustained PTX release behavior in vitro. In vitro cytotoxicity finds that PCDAA‐PTX NPs can accumulate significantly in tumor cells and remain the pharmacological activity of PTX. The in vivo real‐time biodistribution of PCDAA‐PTX NPs is investigated using near‐infrared fluorescence imaging, indicating that the PCDAA‐PTX NPs can effectively target to the tumor site by the enhanced permeability and retention effect in H22 tumor‐bearing mice. Through in vivo antitumor examination, PCDAA‐PTX NPs exhibit superior efficacy in impeding the tumor growth compared to the commercially available Taxol®.

     

混合径角$\lambda$中心有界平均振荡空间的一个特征

在这篇文章中,我们通过Hardy算子交换子$\mathrm{H}_b$与它的对偶算子交换子$\mathrm{H}^*_b$, 其中$b\in {\mathrm{CMOL}^{p_2, \lambda}_{\rm rad}L^{p_1}_{\rm ang}(\mathbb R^n)}$,建立了混合径角$\lambda$中心有界平均振荡空间的一个特征.     

采用分子动力学方法研究氯化钠水溶液的微观结构

溶液的微观结构对溶液的宏观性质具有决定性影响,团簇的存在和溶液不均性的认知是该领域研究的重要进展之一,也是关注的热点.为了考察溶液的微观结构,本文采用分子动力学方法对浓度适中的氯化钠水溶液进行了模拟,获得了各原子(离子)间的径向分布函数和溶液的瞬态图像.通过对比分析Na~+-Cl~-和Cl~--Na~+的径向分布函数,并结合已有研究结果,表明该径向分布函数上第三峰也来源于离子对,发现氯化钠水溶液存在着第三种离子对;上述径向分布函数上的三个峰分别与直接接触离子对、部分间隔离子对和完全间隔离子对相对应,并给出了这三种离子对的瞬态图像.三个时刻下系统瞬态图像的分析结果表明,溶液中存在水分子连续分布的区域和由离子与水分子共同构成的离子团簇.各瞬态图像中水分子连续分布的最大区域的平均尺寸至少为1.43 nm,溶液中部分间隔离子对的比例最大,约为0.68.在同时考虑直接接触离子对和部分间隔离子对时,三个时刻中最大团簇尺度的平均值为1.44 nm,该值约为部分间隔离子对最概然尺寸的3倍;团簇尺寸随团簇中离子数的增加而增大,在团簇中离子数较大时,满足无规行走(自由连接链)模型的结果.这些说明氯化钠水溶...     

Coupling Transition Metal Compound with Single-Atom Site for Water Splitting Electrocatalysis

Single-atom site catalysts (SACs) provide an ideal platform to identify the active centers, explore the catalytic mechanism, and establish the structure-property relationships, and thus have attracted increasing interests for electrocatalytic energy conversion. Substantial endeavors have been devoted to the construction of carbon-supported SACs, and their progress have been comprehensively reviewed. Compared with carbon-supported SACs, transition metal compounds (TMCs)-supported SACs are still in their infancy in the field of electrocatalysis. However, they have also aroused ever-increasing attention for driving electrocatalytic water splitting, and emerged as an indispensable class of SACs in recent years, predominately owing to their inherently structural features, such as rich anchoring sites, surface defects, and lattice vacancy. Herein, in this review, we have systematically summarized the recent advances of a variety of TMC supported SACs toward electrocatalytic water splitting. The advanced characterization techniques and theoretical analyses for identifying and monitoring the atomic structure of SACs are firstly manifested. Subsequently, the anchoring and stabilization mechanisms for TMC supported SACs are also highlighted. Thereafter, the advances of TMC supported SACs for driving water electrolysis are systematically unraveled.     

Influence of <Emphasis Type="Italic">M</Emphasis><Subscript><Emphasis Type="Italic">p</Emphasis></Subscript>-supplemented subgroups on the structure of <Emphasis Type="Italic">p</Emphasis>-modular subgroups

A subgroup K of G is M _p -supplemented in G if there exists a subgroup B of G such that G = KB and TB < G for every maximal subgroup T of K with |K: T| = p ^α. We study the structure of the chief factor of G by using M _p -supplemented subgroups and generalize the results of Monakhov and Shnyparkov by involving the relevant results about the p-modular subgroup O ^p (G) of G.