Naked-Eye Readout of Analyte-Induced NIR Fluorescence Responses by an Initiation–Input–Transduction Nanoplatform

Fluorescence visualization (FV) in the near-infrared (NIR) window promises to break through the signal-to-background ratio (SBR) bottleneck of traditional visible-light-driven FV methods. However, straightforward NIR-FV has not been realized, owing to the lack of methods to readily transduce NIR responses into instrument-free, naked eye-recognizable outputs. Now, an initiation–input–transduction platform comprising a well-designed NIR fluorophore as the signal initiator and lanthanide-doped nanocrystals as the transducer for facile NIR-FV is presented. The analyte-induced off–on NIR signal serves as a sensitizing switch of transducer visible luminescence for naked-eye readout. The design is demonstrated for portable, quantitative detection of phosgene with significantly improved SBR and sensitivity. By further exploration of initiators, this strategy holds promise to create advanced NIR-FV probes for broad sensing applications.     

Local Whittle estimator for anisotropic random fields

A local Whittle estimator is developed to simultaneously estimate the long memory parameters for stationary anisotropic scalar random fields. It is shown that these estimators are consistent and asymptotically normal, under some weak technical conditions. A brief simulation study illustrates a practical application of the estimator.     

High‐Rate,Tunable Syngas Production with Artificial Photosynthetic Cells

An artificial photosynthetic (APS) system consisting of a photoanodic semiconductor that harvests solar photons to split H₂O, a Ni‐SNG cathodic catalyst for the dark reaction of CO₂ reduction in a CO₂‐saturated NaHCO₃ solution, and a proton‐conducting membrane enabled syngas production from CO₂ and H₂O with solar‐to‐syngas energy‐conversion efficiency of up to 13.6 %. The syngas CO/H₂ ratio was tunable between 1:2 and 5:1. Integration of the APS system with photovoltaic cells led to an impressive overall quantum efficiency of 6.29 % for syngas production. The largest turnover frequency of 529.5 h^?1 was recorded with a photoanodic N‐TiO₂ nanorod array for highly stable CO production. The CO‐evolution rate reached a maximum of 154.9 mmol g^?1 h^?1 in the dark compartment of the APS cell. Scanning electrochemical–atomic force microscopy showed the localization of electrons on the single‐nickel‐atom sites of the Ni‐SNG catalyst, thus confirming that the multielectron reduction of CO₂ to CO was kinetically favored.     

α-溴汞化羰基化合物与N-亚硝基乙酰芳胺的反应

用作芳基自由基来源的N-亚硝基乙酰芳胺与α-溴汞化羰基化合物一起加热时,生成溴化芳基汞,副产物及ESR研究说明反应为自由基过程.     

Efficient asymmetric oxidation of sulfides and kinetic resolution of sulfoxides catalyzed by a vanadium-salan system

The asymmetric oxidation of sulfides to chiral sulfoxides with hydrogen peroxide in good yield and high enantioselectivity has been catalyzed very effectively by chiral vanadium-salan [N,N'-alkyl bis(salicylamine)] complex. The salan ligand shows results superior in terms of reactivity and enantioselectivity to those of salen [N,N'-alkylene bis(salicylideneimine)] analogue, and provides the sulfoxide with opposite configuration. The high enantioselectivity of this reaction is the direct result of the asymmetric oxidation. The efficient kinetic resolution of racemic sulfoxides catalyzed by the vanadium-salan system is also described.     

自适应网格技术中的权函数问题研究

利用两个具有解析解的算例研究利用变分原理的自适应网格技术.结果表明,对运动激波算例,权函数考虑二阶导数项比考虑梯度项能更有效地减小误差;对气旋锋生算例,仅以梯度作为权函数亦不能提高精度,考虑速度场、锋生函数分布的权函数能更合理地安排网格.     

Tuning the release rate of volatile molecules by pore surface engineering in metal-organic frameworks

Encapsulation and controlled release of volatile molecules such as fragrances in a designed manner is important but challenging for the flavor and fragrance industry. Here, we report the tuning release of volatile molecules by postsynthetic modification of an amine-terminated metal-organic framework(MOF) MIL-101-NH_2. By amidation, we obtained three MIL-101 MOFs, the trimethylacetamideterminated TC-MIL-101, the benzamide-terminated BC-MIL-101, and the oxalic acid monoamideterminated OC-MIL-101. All the MOFs can efficiently encapsulate volatile molecules. Moreover, we demonstrate that the release profile of volatiles can be widely tuned to sustain the release in several days to months and even over a year using different modified MIL-101 MOFs. We show that the release profiles are correlated with the binding energies between the guest volatiles and pores in MOFs. The pore diffusion and the synergistic transport are the rate-limiting step of the guest molecules from the modified MOFs.     

Bis Crown Ethers( Ⅸ)——Caesium Selective PVC Membrane Electrodes Based on Schif f Base Type of Bis Crown Ethers

Recently, much attention has been focused on the use of neutral carrier species as membrane components to extract ions from aqueous solution into a hydrophobic membrane phase. Some potassium-or caesium-selective electrodes based on bis-benzo-15-crown-5 or bis-benzo-18-crown-6 containing ester or other linkage were prepared by K. Kimura and K. W. Fung. The selective coefficients K_(K,Na)~(pot), K_(Cs,Na)~(pot),or K_(Cs,K)~(pot), K were 2.6×10~(-4), 1.9×10~(-2) and 1.7×10~(-1), respectively.     

加压阳离子交换流洗法分离研究——以H2SO4-MnSO4为流洗剂分离UO22+、U(Ⅳ)和Fe2+及UO22+和Fe3+及其机理

本文发现一种含有Mn²⁺的硫酸流洗剂,可使UO₂²⁺和U(Ⅳ)的扩散常数分别增大20倍和400倍,从而显著地提高了UO₂²⁺和U(Ⅳ)的阳离子色谱效率;并论证了Mn²⁺离子的作用机理。     

多齿配体的合成

苯环上有羟基或甲氧基的苄醇在硫酸存在下与乙腈或丙烯腈作用,得到了相应的酰胺。产率一般在90％以上。乙酰胺水解成二胺后与水杨醛作用生成相应的双Schiff碱。