紫外-可见光光束在TiO_2纳米颗粒胶体中的传输（英文）

紫外光诱导纳米颗粒胶体射流加工技术利用紫外光场对入射纳米颗粒的催化作用实现对工件表面材料的高效去除。为掌握紫外光诱导纳米颗粒胶体射流加工过程中紫外光束在纳米二氧化钛胶体中的传输特性,基于纳米二氧化钛胶体对紫外-可见光的吸收及散射理论,通过系列实验得到紫外-可见光束在不同浓度、吸收层厚度的二氧化钛纳米颗粒胶体中的传输特性及衰减关系。结果表明,为保证足够强度的紫外光能通过纳米二氧化钛胶体照射在工件表面,胶体浓度宜控制在500mol/m3以下,光-液耦合区胶体吸收层的厚度不宜超过20mm。     

Residual symmetry reductions and interaction solutions of the (2+1)-dimensional Burgers equation

In nonlinear physics,it is very difficult to study interactions among different types of nonlinear waves.In this paper,the nonlocal symmetry related to the truncated Painleve′expansion of the(2+1)-dimensional Burgers equation is localized after introducing multiple new variables to extend the original equation into a new system.Then the corresponding group invariant solutions are found,from which interaction solutions among different types of nonlinear waves can be found.Furthermore,the Burgers equation is also studied by using the generalized tanh expansion method and a new Ba¨cklund transformation(BT)is obtained.From this BT,novel interactive solutions among different nonlinear excitations are found.     

Synthesis and electrochemical properties of regular hexahedron α-Fe2O3

Synthesis of α-Fe₂O₃ compound with regular hexahedron shape is firstly reported. X-ray diffraction and scan electron microscope are used to characterize the structure and morphology of the prepared sample, respectively. The average edge length of hexahedron is about 0.9 μm. A reaction mechanism has been proposed. The pH value is a crucial factor for the formation and shape of α-Fe₂O₃. Moreover, electrochemical impedance spectroscopy and charge-discharge test of α-Fe₂O₃ as anode material in lithium ion batteries are evaluated. The data indicate that the synthesized regular hexahedron α-Fe₂O₃ can show better electrochemical properties than that of the commercial.     

Preparation of dendritic‐like CdS by hydrothermal method and its photocatalytic performance

In this article, dendritic‐like CdS has been prepared by a hydrothermal method using thiourea as the sulfur source, and the effects of experimental conditions on the morphologies of CdS have been investigated. The performances of CdS have been analyzed by X‐ray diffraction (XRD), field emission scanning electron microscopy (FESEM), and the fluorescence and photodegradation properties of CdS have also been investigated. The XRD result indicates that the dendritic‐like CdS are of hexagonal phase and they are highly crystallized. Also, the FESEM results show that the ratio of raw material affects the yield of CdS, the reaction time affects the morphology of CdS. The best morphology of CdS is dendritic structures and the length is about 6 μm. The fluorescence spectrum shows three peaks at 470 nm, 513 nm and 547 nm, which indicates that the dendritic‐like CdS mainly emits green and blue fluorescence. Moreover, the dendritic‐like CdS exhibits good photocatalytic activity and its photodegradation rate to methylene blue can reach 92%. The growth mechanism for the formation of CdS with dendritic structure is also described.     

A Supercharged Fluorescent Protein as a Versatile Probe for Homogeneous DNA Detection and Methylation Analysis

Supercharged proteins are a new class of functional proteins with exceptional stability and potent ability to deliver bio‐macromolecules into cells. As a proof‐of‐principle, a novel application of supercharged proteins as a versatile biosensing platform for nucleic acid detection and epigenetics analysis is presented. Taking supercharged green fluorescent protein (ScGFP) as the signal reporter, a simple turn‐on homogenous method for DNA detection has been developed based on the polyionic nanoscale complex of ScGFP/DNA and toehold strand displacement. This assay shows high sensitivity and potent ability to detect single‐base mismatch. Furthermore, combined with bisulfite conversion, this ScGFP‐based assay was further applied to analyze site‐specific DNA methylation status of genomic DNA extracted from real human colon carcinoma tissue sample with ultrahigh sensitivity (4 amol methylated DNA).     

A Complete Switch of the Directional Selectivity in the Annulation of 2‐Hydroxybenzaldehydes with Alkynes

Controlling reaction selectivity is an eternal pursuit for chemists working in chemical synthesis. As part of this endeavor, our group has been exploring the possibility of constructing different natural product skeletons from the same simple starting materials by using different catalytic systems. In our previous work, an isoflavanone skeleton was obtained from the annulation of a salicylaldehyde and an alkyne when a gold catalyst was employed. In this paper, it is shown that a coumarin skeleton can be efficiently obtained through an annulation reaction with the same starting materials, that is, terminal alkynes and salicylaldehydes, by simply switching to a rhodium catalyst. A plausible reaction mechanism is proposed for this new annulation based on isotopic substitution experiments.     

Turn-on fluorescence sensing of cyanide ions in aqueous solution简

A sensitive fluorescent probe, 2,2＇-bisbenzimidazole （L）, for CN has been developed. This structurally simple receptor displays great selectivity for the cyanide anion over other common inorganic anions in an aqueous environment. In addition, further study demonstrates the lower detection of the fluorescence response of the sensor to CN is in 10 9 mol/L range. Thus, the present probe should be applicable as a practical system for the monitoring of cyanide concentrations in aqueous samples.     

Cycloaddition reactions of benzyne with olefins

Some novel cycloaddition reactions based on benzyne and olefins have been developed.These reactions were performed in the absence of a transition metal catalyst,and they displayed good yields.These cycloaddition reactions of benzyne with olefins provide effective routes for synthesizing benzocyclobutenes,biaryl compounds and 9,10-dihydrophenanthrene derivatives.     

The Relationship of Freeze Tolerance with Intracellular Compounds in Baker’s Yeasts

Freeze-tolerant baker’s yeasts are required for the processing of frozen doughs. The present study was carried out to investigate the cell survival rate after frozen storage and the change of fermentability in dough due to frozen storage, and to discuss quantitatively the relationship of freeze tolerance with intracellular trehalose, amino acids, and glycerol, using six types of baker’s yeasts as the test materials. The experimental results showed that the fermentability of yeast cells in frozen dough was strongly correlated with the cell survival rate. The baker’s yeast with a higher level of cell survival rate had a larger increase in the total intracellular compound content after frozen storage, and the cell survival rate increased linearly with increasing total intracellular compound content in frozen yeast cells. Trehalose was a primary compound affecting freeze tolerance, followed by glutamic acid, arginine, proline, asparagic acid, and glycerol. The basic information provided by the present study is useful for exploring the freeze-tolerance mechanisms of baker’s yeast cells, breeding better freeze-tolerant baker’s yeast strains, and developing more effective cryoprotectants.