Solvent‐Free Self‐Assembly for Scalable Preparation of Highly Crystalline Mesoporous Metal Oxides

Mesoporous metal oxides (MMOs) have been demonstrated great potential in various applications. Up to now, the direct synthesis of MMOs is still limited to the solvent induced inorganic‐organic self‐assembly process. Here, we develop a facile, general, and high throughput solvent‐free self‐assembly strategy to synthesize a series of MMOs including single‐component MMOs and multi‐component MMOs (e.g., doped MMOs, composite MMOs, and polymetallic oxide) with high crystallinity and remarkable porous properties by grinding and heating raw materials. Compared with the traditional solution self‐assembly process, the avoidance of solvents in this method not only greatly increases the yield of target products and synthesis efficiency, but also reduces the environmental pollution and the consumption of cost and energy. We believe the presented approach will pave a new avenue for scalable production of advanced mesoporous materials for various applications.     

Bridge Bonded Oxygen Ligands between Approximated FeN4 Sites Confer Catalysts with High ORR Performance

The applications of the most promising Fe—N–C catalysts are prohibited by their limited intrinsic activities. Manipulating the Fe energy level through anchoring electron‐withdrawing ligands is found effective in boosting the catalytic performance. However, such regulation remains elusive as the ligands are only uncontrollably introduced oweing to their energetically unstable nature. Herein, we report a rational manipulation strategy for introducing axial bonded O to the Fe sites, attained through hexa‐coordinating Fe with oxygen functional groups in the precursor. Moreover, the O modifier is stabilized by forming the Fe?O?Fe bridge bond, with the approximation of two FeN₄ sites. The energy level modulation thus created confers the sites with an intrinsic activity that is over 10 times higher than that of the normal FeN₄ site. Our finding opens a novel strategy to manage coordination environments at an atomic level for high activity ORR catalysts.     

Research Progress in the Field of Adsorption and Catalytic Degradation of Sewage by Hydrotalcite‐Derived Materials

With the rapid development of industry and agriculture and the greatly improved living conditions, the resultant gradually deteriorated environments threaten the human beings. Refractory or even toxic pollutants, which are from different industries such as printing and dyeing, pesticides, chemicals, petrochemicals, plastics and rubber, seriously threat the ecosystems and human health. Having the advantages of flexible composition, unique structure, high stability, memory effect, easy preparation and low cost, hydrotalcite compounds have a great potential in sewage degradation and environmental protection. This study focuses on the adsorption and catalytic properties (such as photocatalysis, electrocatalysis and photoelectrocatalysis) of hydrotalcite‐derived materials for treating organic, inorganic and heavy metal ion sewage. The types of adsorption and catalysis, and the effects of various influencing factors on the degradation efficiency were discussed as well.     

In‐situ preparation of porous monolithic polymer inside hollow fiber as a micro‐solid phase extraction device for glucocorticoids in cosmetics

Glucocorticoids have a certain whitening effect on the skin. However, frequent and long‐term use of cosmetics including glucocorticoids is harmful to health. Herein, we proposed a novel micro‐solid phase extraction method for the detection of prednisolone acetate, prednisone, and prednisolone in cosmetics coupled with high‐performance liquid chromatography. In this method, porous monolithic polymer micro‐extraction bars were prepared by “one‐step, one‐pot” in situ photopolymerization combined with sacrificial support in hollow fiber under water atmosphere. The crucial factors such as pH of sample solution, extraction, and elution times that influence micro‐extraction were optimized and found to be 9.0, 2 h, and 32 min, respectively. Under the optimum experimental conditions, the linear range of the calibration curves were from 5.0 to 2000 µg/L with correlation coefficients (R²) between 0.9922 and 0.9996. The limit of detection and limit of quantification were 1.5 µg/L and 5.0 µg/L, respectively, and the recoveries were found to be in range of 69.0–113.3%. The analysis of precision for intraday and interday were less than 10.40 and 10.59%. The device has been successfully achieved photopolymerization under water atmosphere. The results indicated that this method is simple, accurate, and satisfactory for the pretreatment and determination of glucocorticoids in complex cosmetics samples.     

Numerical and Experimental Investigation of Liquid Residue in 90° Bend Microchannel Based on Gas–Liquid Two-Phase Flow

The microfluidic chip for nucleic acid detection in vitro is an essential application of microfluidic technology to the process of in vitro diagnosis. The 90° bend microchannels in chip designed for facilitating assay reagent delivery may cause reagent residues and cast mutual contamination between detection reagents, which significantly affects the detection accuracy. In this paper, a two-dimensional gas–liquid two-phase flow model is constructed to simulate the liquid residue phenomenon. Using the results of simulation, the residual liquid generation can be observed and the area of residual liquid can be obtained. The accuracy of the numerical simulation is verified by comparison with the experimental results. The effects of the fillet radius R, the diameter ratio d₁/d₂ of the vertical to horizontal sections, the flow velocity v, and the surface roughness R_a on the residual amount are studied. We find that the fillet radius is inversely proportional to the residual amount within the range v = 20–100 mm/s and there is almost no liquid residue in the channel when the radius increases to R = 1 mm. When the channel diameter ratio d₁/d₂ increases, the liquid residual amount also increases by approximately 98%. The increased surface roughness R_a significantly increases the residual amount. The results of this study provide a reference for the optimal design of microchannels on chips.

     

Authentication perpendicular arrays APA1(2, 5, v)

Authentication perpendicular arrays APA_λ (t, k, v), as a special kind of perpendicular arrays, are introduced by D. R. Stinson in constructing authentication and secrecy codes. In this article, we improve the existence results for APA₁(2, 5, v) and show that such a design exists if and only if v ≥ 5 is odd, except v = 7 and possibly excepting v = 9, 13, 15, 17, 33, 39, 49, 53, 57, 63, 69, 73, 87, 89, 97, 113, 137, and 213. © 1996 John Wiley & Sons, Inc.     

对流层夜间化学研究

NO3自由基与N2O5是对流层夜间化学的关键物种。一方面NO3与O3等组分是夜间大气中的重要氧化剂,与它们的反应是生物排放挥发性有机物（VOCs）的主要汇;另一方面NO3与N2O5和雨滴或气溶胶颗粒物发生的异相反应则是大气中氮氧化合物NOx（NO,NO2）的主要清除过程,从而可以减轻对流层臭氧污染。研究它们的化学反应性质及对其进行实地测量,对深入理解大气氧化过程和全面了解区域乃至全球大气自净能力有重要意义。本文总结了近年来有关夜间化学的研究成果,介绍了以NO3和N2O5为中心的基本夜间化学过程、对流层中NO3与N2O5的源与汇以及外场测量技术的最新研究进展,并提出了尚待解决的一些问题。     

Mg/Zn/Al类水滑石的热分解和水化性能研究

采用共沉淀法制备了Mg2Al1、Zn2Al1和Mg1Zn1Al1LDHs,利用XRD和SEM表征手段,对它们的热分解及焙烧物在Na2CO3溶液中恢复层状结构的能力进行了对比研究。结果表明,在400～700℃温度范围内,Zn2Al1LDH和Mg2Al1LDH的焙烧物中均出现氧化物相(ZnO和MgO)和尖晶石相(ZnAl2O4和MgAl2O4相);而Mg1Zn1Al1LDH的焙烧物中始终以ZnO相为主,仅在700℃时出现微弱的MgAl2O4相。三种焙烧物恢复层状结构的能力为:Mg1Zn1Al1LDO>Mg2Al1LDO>Zn2Al1LDO,其与焙烧物组成有关。原始LDHs和水化LDHs均呈片状。     

A Novel 3D Na(I) Coordination Polymer Constructed by 3,5-Bis(4'-Carboxy-Phenyl)-1,2,4-Triazole: Synthesis,Crystal Structure,and Photocatalytic Property

Crystallography Reports - A novel 3D metal coordination polymer, {[Na4(µ2-H2O)(DMF)2(BCT)2]?DMF}n (I) (DMF = N,N-dimethylformamide, H2BCT =...